Heat fixable high energy radiation imaging film

ABSTRACT

Described is a radiation sensitive imaging film containing a heat fixable radiation sensitive element, e.g., a diacetylene, of the formula: R--C.tbd.C--C.tbd.C--R&#39;, where R and R&#39; are, e.g., both --CH 2  --O--CONH--(CH 2 ) 5  CH 3 . After exposure to X-radiation during diagnostic or X-ray therapy, the resulting image can be permanently dry fixed by a short heating step and then stored for a long period. Processes for making the film, new binder-convertor systems, and a device incorporating the film are described as well as other imaging, diagnostic and therapeutic methods utilizing the film in high energy radiation applications in the health care field.

ACKNOWLEDGMENT

The major part of this work was supported from Research Grants (R43CA49347-01, R43 CA49347-02, and R43 CA49347-03) from the National CancerInstitute, U.S. Department of Health and Human Services under the SmallBusiness Innovation Research Program.

CROSS REFERENCE TO RELATED APPLICATIONS

The instant case is a continuation-in-part application of the followingU.S. applications: Ser. No. 07/970,986, filed Nov. 2, 1992, nowabandoned, which is a continuation application of Ser. No. 07/506,272,filed Apr. 9, 1990, now abandoned; and Ser. No. 07/973,192, filed Nov.2, 1992, now abandoned, which is a continuation application of Ser. No.07/506,273, filed Apr. 9, 1990, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a radiation sensitive film for imaging andmonitoring high energy ultraviolet, electrons, X-rays, and neutronsutilizing as the radiation sensitive element; a radiation polymerizablediacetylenic composition, which can be fixed during processing simply byheating after exposure. The invention also relates toconvertor-complexed polymeric binder compositions useful in the film forconverting high energy incident radiation into lower energy radiation toenhance image formation. Processes for preparing emulsions of radiationsensitive compounds for use in the film are also provided.

2. Brief Description of Prior Art

High energy radiation, including that having energy higher than 4 eV,such as short wavelength UV light, X-rays, gamma rays, electrons,neutrons, and laser radiation are used for a variety of applications,such as curing of coatings and cross linking of polymers, recordingimages and information, radiography, nondestructive testing anddiagnostic and radiation therapy.

Currently, silver halide film, composed mainly of an emulsion of silverbromide/iodide in gelatin is widely used as the film for recordingimages and information, diagnostic and industrial radiography andmonitoring radiation therapy and dose. The main advantages of silverhalide film are (1) high spatial resolution, (2) image distributionacross a plane which can be obtained from a single exposure and (3)information can be stored permanently. However, silver halide film hasmany disadvantages and drawbacks: (a) it requires protection fromambient light until fixed, (b) the developing and fixing processes are"wet" and chemical based, and require about five minutes developingtime, and the concentrations of individual solutions and chemicals, timeand temperature of developing and fixing must be strictly controlled.However, it is desired in the art to have a self-developing, fast, dryfixing film which is not affected by white light. There is further adefinite need for an inexpensive, dry-processing film for monitoringhigh energy radiation dosages, storing information and images,nondestructive testing of industrial parts, medical diagnosis, qualitycontrol and verification of radiation therapy procedures which has theadvantages and desired features of silver halide film with essentiallynone of its major disadvantages and drawbacks.

New photosensitive materials are constantly being searched for toprovide new film devices. One such group of materials being evaluatedare the polymerizable diacetylenes, R--C.tbd.C--C.tbd.C--R, where R is asubstituent group, which diacetylenes polymerize in the solid stateeither upon thermal annealing or exposure to high energy radiation [Adv.Polym. Sci., 63,1 (1984)]. The term diacetylene(s) is used herein todesignate a class of compounds having at least one --C.tbd.C--C.tbd.C--functionality. The solid monomers are colorless or white, the partiallypolymerized diacetylenes are blue or red, while the polydiacetylenes aremetallic being usually a copper or gold color. Polydiacetylenes arehighly colored because the "pi" electrons of the conjugated backbone aredelocalized. The color intensity of the partially polymerizeddiacetylenes is proportional to the polymer conversion.

A number of patents have been issued on the synthesis and use ofconjugated polyacetylenic compositions. as radiation dosimeters,temperature monitors, and time temperature indicators.

The use of diacetylenes including those having carboxylic acidsubstituents and their derivatives in photographic and other relatedarts is disclosed in several U.S. Patents, such as, U.S. Pat. Nos.3,501,297 and 3,679,738 (issued to Cremeans), U.S. Pat. No. 3,501,302(issued to Foltz), U.S. Pat. No. 3,501,303 (issued to Foltz et al), U.S.Pat. No. 3,501,308 (issued to Adelman) and U.S. Pat. Nos. 3,743,505;3,844,791 & 4,066,676 (all three issued to Bloom). These patentsdisclose dispersions in resin, gelatin, or gum matrices of certaindiacetylene crystals for directly imaging photo-reactive compositions.Light exposed areas are evidenced by a color change. A quantumefficiency of 8 to 16 is reported. For the use of diacetylenes indiagnostic X-ray film imaging, significantly high quantum yields arerequired.

Diacetylenes are not sensitive to visible radiation (long wavelength).Luckey and Boer in U.S. Pat. No. 3,772,027 disclose a diacetylenicphotosensitive element containing inorganic salts, such as titaniumdioxide, zinc oxide, cadmium iodide, and cadmium sulfide as sensitizersto make the element sensitive to visible radiation. Another similarpatent (U.S. Pat. No. 3,772,028) issued to Fico and Manthey discloses aphotosensitive element sensitized to visible radiation by the additionof pyrylium salts including thiapyrylium and selenapyrylium salts.Amplification of poorly imaged crystalline diacetylenic compositions isobtained in U.S. Pat. No. 3,794,491 (issued to Borsenberger et al).Faint images are enhanced through post-exposure irradiation. Thesepatents describe formulations and processes for making diacetylenessensitive to longer wavelength (lower energy) radiation, such as visibleso that the film can be used as a photographic film for visible light.However, there is no report on the sensitization of diacetylenes toshorter wavelength (higher energy) radiation, such as X-rays. Suchsensitization to higher energy radiation is desirable for making, forexample, diagnostic X-ray film.

In order to increase the spatial resolution of images obtained withdiacetylenic imaging compositions, Rasch in U.S. Pat. No. 3,882,134,prepared compositions having a much finer grain structure than reportedbefore. He described the use of vapor deposition to facilitate theisolation of fine microcrystals.

Ehrlich in U.S. Pat. No. 3,811,895 disclosed the use of organometallicsas sensitizers and the use of such sensitized systems as X-ray filmmedia. Lewis, Moskowitz, and Purdy in U.S. Pat. No. 4,734,355 disclose aprocessless recording film made from crystalline polyacetyleniccompounds. They also disclosed a process of dispersing crystallinepolyacetylenic compounds in a non-solvating medium to a concentration ofabout 2 to 50% polyacetylene crystalline solids and aging saiddispersion before drying on a substrate. The sensitivity of the obtainedfilm is low and hence exposure of at least a kilorad of radiation isrequired to produce the image. Their gelatin/diacetylene mixturerequires prolonged aging at low temperature. However, it would bedesirable to have a process which does not require aging of theemulsion. Fine crystals (grain size) are desirable for certainapplications, such as microfilm and larger crystals can be used forother applications, such as radiation therapy film so that higherradiation sensitivity can be obtained. It is also desirable in the actto have a process to control the diacetylene crystal size.

Guevara and Borsenberger in U.S. Pat. No. 3,772,011 describe print-outelements and methods using photoconductors and crystallinepolyacetylenic compounds in contact with a photoconductive layer.Visible images are obtained when these layers are contacted with theapplication of an electric potential. In the absence of an appliedpotential, the elements described are stable under normal room-lighthandling conditions. Guevera et al in U.S. Pat. No. 3,772,011 provides adiacetylenic composition which undergoes direct image-wisephoto-polymerization to a highly colored polymeric product whenelaborated into a layer of micro-crystals contiguous to aphoto-conductive layer. Such polymerization takes place upon exposureduring the application of an electric potential across the layers. Insome cases, an organic photoconductor may be included in the layer ofcrystalline polyacetylenes.

Use of diacetylenic compositions for photoresists has been disclosed inU.S. Pat. Nos. 3,840,369; 4,581,315 and 3,945,831.

Patel in U.S. Pat. Nos. 4,235,108; 4,189,399; 4,238,352; 4,384,980 hasdisclosed a process of increasing the rate of polymerization bycocrystallization of diacetylenes. Patel and others in U.S. Pat. Nos.4,228,126; and 4,276,190 have described an inactive form of diacetylenesfor storing and method of rendering them active prior to use by solvent,vapor and/or melt recrystallization.

Mong-Jon Jun at el (U.S. Pat. No. 3,836,368) describe2,4-hexadiyn-1,6-bis(n-hexyl urethane), referred to here in as "166",which turns red upon short wavelength UV irradiation (See Example 3 inthe Patent). They prepared a coating formulation by adding water to asolution of 166 in polyvinylpyrrolidone in methanol. The UV exposedcoating was red, and it changed to a black color after heating at 55° C.and became inactive to UV light. Although 166 is sensitive to UVradiation, the reactivity is not sufficient to use it for applications,such as diagnostic X-ray film. There is a need to increase thereactivity of 166 so that images can be obtained at a lower radiationdose. We repeated the process described by Jun et al and prepared acoating of 166 by the process disclosed in U.S. Pat. No. 3,836,368. Weobtained undesirably large crystals and hence an opaque coating. Thus,there is a need in the art for a film device which contains heat fixablediacetylenes, is highly radiation sensitive, preferably transparent andwhich can be quickly heat fixed in a dry process providing highresolution imaging.

None of the above described patents describe a film which issubstantially transparent, highly sensitive to short wavelength UV,X-ray, electron, gamma ray, or neutron radiation and contains aradiation sensitive element composed of at least one polymerizablediacetylenic compound and a convertor which emits radiation ofwavelength shorter than 350 nm when contacted with high energyradiation, which when heated becomes fixed and turns into a bluepermanent image. Further, use of a polymeric binder e.g.,polyethyleneimine, complexed with a convertor material is also notreported. Furthermore, there is no report of a process for making anemulsion of a diacetylene which does not require aging and provides thedesired micro-size crystals for preparing transparent films. There arefurther deficiencies in the prior art with respect to the field ofradiation sensitive imaging and monitoring devices as described below.

Silver halide film is not very sensitive to diagnostic X-ray radiation.X-ray images are amplified by placing the film between two fluorescencescreens. Intensifying screens are luminescent materials and usuallyconsist of a crystalline host material to which is added a trace of animpurity. Luminescence in inorganic solids usually originates at defectsin the crystal lattice (Thomas F. Soules and Mary V. Hoffman,Encyclopedia of Science and Technology, Vol. 14, 1987, pp527-545). Thephosphor of the fluorescence screen absorbs X-rays and emits whitelight. Intensifying screens made with calcium tungstate phosphors havebeen in use since the time of Roentgen. Around 1972, a new phosphor,gadolinium oxysulfide was developed which emits in the green region andfilm sensitized to absorb green light was developed. About the same timeother phosphors, such as barium fluorochloride and lanthanum oxybromide,which emit in the blue region, were developed. A large number ofphosphors have been reported in the literature including terbiumactivated rare earth oxysulfide (X₂ O₂ S where X is gadolinium,lanthanum, or yttrium) phosphors (T. F. Soules and M. V. Hoffman,Encyclopedia of Chemical Technology, Vol.14, pp 527-545, 1981 andreferences quoted therein). Gadolinium and tungsten have very highatomic numbers and also have a high energy absorption coefficient. Thefollowing combinations have been used for this purpose: GdOS:Tb(lll),LaOS:Tb(lll), LaOBr:Tb(lll), LaOBr:Tm(lll), and Ba(FCl)₂ :Eu(ll). Anumber of patents e.g. U.S. Pat. Nos. 5,069,982; 5,173,611; 4,387,141;and 4,205,234 are representative and have been issued. Among thehundreds of phosphors reported, the literature search reveals that mostof them are blue-, green-, or long wave-UV emitting phosphors uponexcitation by X-ray. Some of them emit long wavelength blue light, forexample, U.S. Pat. No. 4,719,033. No one has so far reported an X-rayscreen with a short-wave UV emitting (e.g., wavelength shorter than 275nm) phosphor.

Convertors/phosphors are usually used as a screen in form of a finepowder dispersed in a polymeric binder. The screens are placed incontact with the emulsion of silver halide film during X-rayirradiation. The prior art does not describe a convertor/phosphor whichis in the form of a transparent coating being a solid solution orcomplex of a convertor with a polymeric binder. The use of theseconvertors in the under coat, radiation sensitive coat and top coat ofthe device is also not described.

Polymers are widely used as binders for a variety of applicationsincluding paints and X-ray film coating. Though other polymers areproposed, gelatin is a widely used binder for silver halide and otherphotosensitive materials including diacetylenes. Many polymers have theability to form complexes with inorganic compounds. However, there is noreport on the use of polymeric complexes as binders for the radiationsensitive formulations, such as diacetylenes.

Polyethyleneimine, referred herein as PEl, forms complexes with a numberof inorganic and organic compounds, see Polym. Sci., Vol. 15, pp751-823, 1990 by S. Kobayashi and J. Polymer Science: Part A: PolymerChem., Vol. 28, pp. 741-758 (1990) by Y. T. Bao and C. G. Pitt. However,there is no report on use of polyethyleneimine and its complexes asbinders and convertors for radiation sensitive films.

Emulsions are usually prepared by homogenizing/emulsifying twoimmiscible liquids, e.g., a water immiscible solvent (e.g.,ethylacetate) with water using an emulsifying agent, such as asurfactant. For example, U.S. Pat. No. 4,734,355 describes this type ofsystem, e.g., diacetylene dissolved in water immiscible solvent, such asethylacetate and emulsified with gelatin solution in water at highspeed. As the solvent used is a good solvent for diacetylenes, themethod requires that the emulsion be chilled to a low temperature, andthe solvent removed and aged. There is no report on making of anemulsion of diacetylenes without a binder and later mixing the emulsionwith a binder. Furtiler, there is no report on preparation of emulsionof a radiation sensitive material, such as diacetylene without using aorganic solvent. Further, there is no report on quenching the emulsionto a very low temperature, e.g., liquid nitrogen temperature, to freezethe emulsion and inducing crystal growth by thawing the frozen emulsion.

SUMMARY OF THE INVENTION

We have discovered that a self-developing, dry fixing film device formonitoring, recording and imaging with radiation, such as UV light,electrons, X-rays, neutrons, or gamma rays, can be made by the use of atleast one heat fixable conjugated diacetylene, a binder, such aspolyethyleneimine, complexed with a converter material, capable uponradiation with high energy electrons, x-rays, gamma rays, neutrons, ofgenerating secondary radiation which is capable of inducingpolymerization of the heat fixable diacetylene to form a colored image.

Particularly useful is a specific diacetylene (R--C.tbd.C--C.tbd.C--R),166 where [R=--CH₂ OCONH(CH₂)₅ CH₃ ] and a few closely relateddiacetylenes which have several unique properties, such as highradiation reactivity, low thermal reactivity, crystallization to aninactive phase from melt, and thus heat fixable. In addition, 166undergoes a red-to-blue color change when the partially polymerized 166is heated near or above its melting point. A preliminary toxicity studyindicates that 166 is nontoxic.

We have also discovered that certain other diacetylenes such as 155[R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₄ CH₃ ], 156[R'--C.tbd.C--C═C--R", where R'=--CH₂ OCONH(CH₂)₅ CH₃ and R"=--CH₂OCONH(CH₂)₄ CH₃ ] and 16PA [R'--C═C--C═C--R", where R'=--CH₂ OCOCH₂ C₆H₅ and R'=--CH₂ OCONH(CH₂)₅ CH₃ ] also have very high radiationreactivity and undergo a phase change, from an active to inactive, whenheated near or above their melting points and can be used for making thefilm.

We have also unexpectedly found that the other related diacetylenes,such as 155, 156 and 16PA which can cocrystallize with 166, can increasethe radiation reactivity. Specifically, the 85:15 mixture of 166:156 isa preferred diacetylene mixture for the film. We have also discoveredthat diacetylenes such as 155, 156 and 16PA each have very highradiation reactivity and transform to an inactive phase upon heatingnear or above their melting points.

By this invention there is provided a self-developing film fordeveloping an image from exposure to X-ray, gamma ray, electron, orneutron radiation comprising at least one conjugated diacetylene, orcocrystallized mixture thereof, capable of undergoing a color changeupon polymerization when contacted with ultraviolet light, X-rays, alphaparticles,, or electrons, thereby forming an image; a binder; aconvertor, wherein said convertor is a material capable of emittingultraviolet light, low energy X-rays, alpha particles, or electrons uponcontact with higher energy X-ray, gamma ray, electron, or neutronradiation; wherein said image is capable of being fixed by heating saiddiacetylene at or above its melting point, or at the temperature atwhich the diacetylene undergoes a phase change to a radiation inactivephase.

Further provided is the above film further comprising: (a) at least onelayer containing said at least one conjugated diacetylene, orcocrystallized mixture thereof, capable of undergoing a color changeupon polymerization induced by ultraviolet light, X-rays, alphaparticles, or electrons, thereby forming a colored image; (b) at leastone layer containing said binder and said convertor being incombination, being a complex or solid solution, wherein said convertoris a material capable of emitting ultraviolet light, low energy X-rays,alpha particles, or electrons upon contact with higher energy X-ray,gamma ray, electron, or neutron radiation; (c) a substrate upon whichsaid layers (a) and (b) are deposited thereon, wherein layer (a) andlayer (b) are capable of being combined into one layer (ab), and saidcolored image is capable of being fixed by heating said diacetylene ator above its melting point, or at the temperature at which thediacetylene undergoes a phase change to a radiation inactive phase.

Furthermore, there is also provided: a self-developing film fordeveloping an image from exposure to ultraviolet or laser radiationcomprising at least one conjugated diacetylene, or cocrystallizedmixture thereof, capable of undergoing a color change uponpolymerization when contacted with ultraviolet or laser radiation,thereby forming an image, and a binder, forming a transparent film,wherein said image is capable of being fixed by heating said diacetyleneat or above its melting point, or at the temperature at which thediacetylene undergoes a phase change to a radiation inactive phase.

We have also discovered a process for synthesis of a co-crystallizedmixture of two or more diacetylenes in a single step, preferably in onepot. Specifically, the 85:15 mixture of 166:156 can be prepared by firstreacting 7.5 mole percent of n-pentyl isocyanate with2,4-hexadiyn-1,6-diol and then adding 92.5 mole percent ofn-hexylisocyanate.

By this invention there is further provided a process for producing anasymmetrical diacetylene comprising: (a) contacting a diacetylene diolwith a first organic reagent, which can react with one of the alcoholgroups of the diol to form a new organic functional group, wherein themolar ratio of the diacetylene diol: first organic reagent is greaterthan 1:1, in a solvent in the presence of a catalyst and a base at atemperature at 0° to 100° C.; (b) contacting the reaction mixture fromstep (a) with a second organic reagent, in a molar ratio of the startingdiacetylene diol: second organic reagent is less than 1:1, which canform the same new functional group as in (a) or a different functionalgroup; (c) recovering said asymmetrical diacetylene from step (b).

We have also discovered that polymeric systems which form complexes orsolid solutions with organic and inorganic compounds are extremelyuseful as binder/convertor compositions for radiation sensitivecompounds, such as diacetylenes. Polyethyleneimine, (--CH₂ CH₂NH--)_(n), is a preferred polymer because it is water-soluble and formscomplexes and/or solid solutions with a large number of inorganiccompounds, such as boric acid and barium iodide which can be used asconvertors for neutrons and X-ray radiation, respectively. A complex ofpolyethyleneimine (PEl) and boric acid (BA), referred herein as PEl/BA,is a preferred binder. This binder forms a transparent coating, andmaintains the high radiation reactivity and low thermal reactivity ofdiacetylenes. This binder will form complexes with known convertors andphosphors, which when irradiated with high energy radiation, includingthermal neutrons, emit lower energy radiation, such as UV light, X-rays,electrons, protons, and alpha particles which are capable of introducingchemical changes in the radiation sensitive materials, e.g.,polymerization of diacetylenes. The convertors are also referred to asphosphors, fluorescence materials and screens herein.

By this invention there is further provided a self-developing filmcomprising at least one radiation sensitive material excluding anon-heat fixable conjugated diacetylene, a polymeric binder, e.g.,polyethyleneimine, associated with a convertor, in a complex or solidsolution, upon contact with high energy X-ray, gamma ray, neutrons,electrons, or laser radiation capable of forming an image.

We have further discovered that the images on the film can besubstantially amplified by about a few orders of magnitude byincorporating the above referred to convertors into the substratum, theradiation sensitive layer and the top coat layers of the device. Thefilm devices can be prepared with a subcoat and top coat containingconvertors or fluorescence materials. A film containing a convertor, forexample boric-10 acid, in the subcoat, radiation sensitive coat and thetop coat is highly sensitive to thermal neutrons. Similarly, a filmcontaining convertors, such as barium iodide and lead iodide in thesubcoat, radiation sensitive coat and top coat is about times moresensitive to diagnostic x-rays, e.g., 60 KeV compared to 10 MeV X-ray,as compared to same film without the added convertors. Methods ofintensifying the images with screens are also provided. The images canbe further amplified by placing the said film in contact with imageintensifying screens containing convertors during the irradiation.

We have furthermore invented processes of preparingemulsions/dispersions of binder/convertor compositions in associationwith the radiation sensitive element, e.g., diacetylene. The processesare exemplified with radiation sensitive formulations, such asdiacetylenes. The term emulsion or dispersion is used for a fluid,semisolid or solid formulation where a composition is suspended in formof crystals or liquid droplets in a liquid or solid medium. The processcan be used for a wide variety of compositions including a binder,convertor, and radiation sensitive element.

By this invention there is further provided a process for producing asuspension of microcrystals of a diacetylene in an aqueous film formingmedium, involving forming an emulsion containing a diacetylene, binder,convertor, water, organic solvent, and surfactant, cooling the emulsion,allowing the solvent and water to evaporate leaving a film, theimprovement which comprises using a totally or partially water-misciblesolvent in forming the emulsion and cooling the emulsion by contactingit with liquid nitrogen prior to solvent and water evaporation.

The emulsions can be prepared by homogenizing a mixture containing theproper proportions of a solution of a convertor compound, a solution ofa binder, solution of a radiation sensitive compound, and an emulsifyingagent, at high speed and elevated temperature (e.g., 50° C.). Theprocesses of the present invention provide stable fine emulsions, andmicroemulsions of diacetylenes at elevated temperatures. We have alsodiscovered methods of making emulsions at high temperature without oneor more of the following basic components for making an emulsion: (1)solvent for diacetylene, (2) solvent for binder, (3) binder, and (4)emulsifying agent. We have also discovered processes for makingnonaqueous emulsions and semiaqueous emulsions as precursor materialsfor the radiation sensitive film.

We have also discovered processes of cooling the emulsions at a lowertemperature for controlled crystallization of compounds, such asdiacetylenes. In order to prevent agglomeration of emulsion droplets,the emulsions are solidified by pouring into liquid nitrogen.

We have also discovered means of controlling the size of the crystals ofthe compounds particularly diacetylenes, by controlling the effects ofmany parameters, including (1) the nature arid concentrations of thecompounds, i.e., diacetylenes, solvents, binders, and emulsifiers, (2)temperature and degree of homogenization, (3) rate of quenching theemulsion, (4) temperature at which the emulsions are cooled, and (5)temperature of crystal growth. The nature and size of the crystals arealso dependent upon the state of the emulsion upon cooling, i.e.,whether the emulsion becomes solid or remains liquid.

We have also discovered a method of making the emulsions of radiationsensitive materials, e.g., diacetylenes, which involves making anemulsion of a solution of diacetylenes with a solution of a binder,quenching the emulsion at a lower temperature to freeze the emulsionquickly and then thawing the solid emulsion at a higher temperature forgrowing crystals of the diacetylenes. The preferred temperature andmedium for quenching the emulsion is liquid nitrogen. For example, anemulsion of diacetylene solution in methylethylketone (MEK), PEl/BA inwater and a surfactant can be prepared by high speed homogenization at60° C. The emulsion is poured into liquid nitrogen to freeze theemulsion. The frozen emulsion does not develop color upon 254 nm UVirradiation. The crystal size is controlled by controlling the thawingtemperature, The emulsion is thawed at about -20° C. for the controlledgrowth of the diacetylene crystals. This method provides micron andsubmicron sized single crystals of the diacetylenes. The radiationsensitive film device can be prepared by coating the emulsion on asubstrate, such as polyester film, skin and paper.

By this invention there is further provided in a process for producing asuspension of microcrystals of a diacetylene in an aqueous film formingmedium, involving forming an emulsion containing a diacetylene, binder,convertor, water, organic solvent, and surfactant, cooling the emulsion,allowing the solvent and water to evaporate leaving a film, theimprovement which comprises using a totally or partially water-misciblesolvent, in forming the emulsion and cooling the emulsion by contactingwith liquid nitrogen prior to solvent and water evaporation.

The invention also provides a means of protecting theradiation-sensitive film from ambient ultraviolet light. The film can beprotected from ambient UV light by incorporating an appropriate amountof UV absorbers, such as maleic acid, sodium salicylate, benzophenone,or benzophenone tetracarboxylate into the top coat. The UV absorbers arenot added into the top coat when screens emitting UV lights are used toamplify the image.

Also provided are flexible, non-brittle polymeric inorganic complexesuseful in radiation sensitive films. Polymeric inorganic complexes,e.g., PEl/BA, are often brittle. A process of plasticization is furtherprovided to make the coating pliable. The nature of the plasticizer willdepend upon the polymeric complex. For example, the PEl/BA complex canbe plasticized by adding an appropriate amount of fatty chain acids,e.g., propionic acid. Plasticization can also be achieved by incomplete,less than 1:1, complexation of PEl, in which an excess of PEl ispresent.

By this invention there is further provided a self-developing film fordeveloping an image from exposure to ultraviolet or laser radiationcomprising at least one conjugated diacetylene, or cocrystallizedmixture thereof, capable of undergoing a color change uponpolymerization when contacted with ultraviolet or laser radiationthereby forming an image, and a binder, forming a transparent film,wherein said image is capable of being fixed by heating said diacetyleneat or above its melting point, or at the temperature at which thediacetylene undergoes a phase change to a radiation inactive phase.

Methods for the utilization of the radiation-sensitive film are alsoprovided. The film can be used for a variety of applications includingidentification of items, a film for recording images and information,diagnostic and industrial radiography and monitoring radiation therapyand dose.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. A schematic cross section of one embodiment of the film deviceof the invention where the substrate is coated on one side with theradiation sensitive layer.

FIG. 2. A schematic cross section of another embodiment of the filmdevice where the substrate is coated on both sides with the radiationsensitive layer.

FIG. 3. Visible spectra of partially polymerized 8515 film irradiatedwith different doses of 10 MeV X-ray radiation.

FIG. 4. The partially polymerized 8515 film of FIG. 3 fixed by annealingat 80° C. for 5 minutes.

FIG. 5. An X-ray photograph, using the 8515 film, of a hand phantomtaken at 200 rads of 100 KeV X-rays.

BRIEF DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The film device can be best described by reference to the FIG. 1.Referring to FIG. 1, the film device in its simplest form is comprisedof a substrate 10 having at least one radiation sensitive layer 30comprised of at least one radiation polymerizable diacetyleniccomposition 32 and optionally a convertor 34, which can also be presentin other layers, e.g. 40 and 20, for converting high energy incidentradiation to low energy radiation, dispersed, dissolved, or complexed ina polymeric binder 36. A plasticizer, 37 can also be present where thebinder and convertor are present, e.g., in the layer 30 to provideflexibility to the coating. The substrate 10 may have a substratumlayer, i.e. undercoat, 20, which can also contain additives, such asconvertors 34, for increasing adhesion between the substrate 10 and theradiation sensitive layer 30. The radiation sensitive layer, 30 may havetop coat 40 which may contain additives, such as a convertor 34. Inorder to protect the radiation sensitive layer from ambient light andmechanical abuses (scratches/abrasion) the device can also have aprotective layer 50 which can also contain additives, such as UVabsorbers 38. The substrate 10, the substratum 20, and the top coat 40,may contain other additives, especially the convertor 34 for convertinghigh energy incident and secondary radiation to lower energy radiationwhich can initiate polymerization of diacetylenic composition 32. Theimage can be amplified by placing the film in contact with a screen,being a phosphor layer 60, on a substrate 70.

The intensity of the image can be doubled as illustrated in FIG. 2 byhaving the radiation sensitive element 30, undercoat 20, top coat 40,protective coat 50, on both sides of the substrate 10, and can befurther amplified by placing the film in contact with a phosphor layer60 and phosphor support 70. The top coat 40, irradiation sensitive coat30, undercoat 20 and protective player 50, can individually andcollectively contain the same or different additives, such a convertorto amplify the image.

In general, the radiation sensitive layer 30 contains a diacetylene 32and a binder 36 in a weight ratio by parts of 10:1 to 0.01:1 andpreferably 1:1; and can also contain the diacetylene 32 and convertor 34in a weight ratio by parts of 1:0.001 to 1:5 and preferably 1:0.1.

The radiation sensitive layer 30 generally is about 1 to 50 micronsthick and preferably 5 to 20 microns thick; the thickness of thesubstrate 10 is generally 10 to 300 microns thick and preferably 50 to200 microns thick; the substratum layer is 0.5 to 50 microns thick andpreferably 1 to 5 microns thick; the protective layer 50 is generally0.5 to 15 microns thick and preferably 1 to 5 microns thick.

The radiation sensitive diacetylene compositions applicable herein arethose having general formula, R'--C.tbd.C--C.tbd.C--R", where R' and R"are the same or different substituent groups. Though this class ofdiacetylenes is preferred, other diacetylenes having the followinggeneral formulas can also be used:

(1) Higher acetylenes: R'--(C.tbd.C)_(n) --R", where n=3-5,

(2) Split di and higher acetylenes: R'--(C.tbd.C)_(m) --Z--(C.tbd.C)_(o)--R", where Z is any diradical, such as --(CH₂)_(n) -- and --C₆ H₄ --,and m and o is 2 or higher,

(3) Polymeric di and higher acetylenes: [--A--(C.tbd.C)_(n) --B--]_(x),where A and B can be the same or different diradical, such as--(CH₂)_(n) --, --OCONH--(CH₂)_(n) --NHCOO--, and --OCO(CH₂)_(n) OCO--.Where R' and R" can be same or different groups.

The preferred diacetylenes include those where R' and R" are selectedfrom:

(CH₂)_(b) -H

(CH₂)_(b) OH

(CH₂)_(b) -OCONH--R1

(CH₂)_(b) --O--CO--R1

(CH₂)_(b) --COOH

(CH₂)_(b) --COOM

(CH₂)_(b) --NH₂

(CH₂)_(b) --CONHR1

(CH₂)_(b) --CO--O--R1

where b=1-10, preferably 1-2, and R1 is an aromatic radical, e.g. C₄ -C₆alkyl or phenyl, and M is a cation, such as Na⁺ or (R1)₃ N⁺.

The preferred diacetylenes are the derivatives of 2,4-hexadiyne,2,4-hexadiyn-1,6-diol, 3,5-octadiyn-1,8-diol, 4,6-decadiyn-1,10-diol,5,7-dodecadiyn-1,12-diol and diacetylenic fatty acids, such astricosa-10,12-diynoic acid (TC), pentacosa-10,12-diynoic acid (PC), andcocrystallized mixtures thereof. The most preferred derivatives of thediacetylenes, e.g. 2,4-hexadiyn-1,6-diol, are the urethane and esterderivatives. The following are some of the preferred derivatives of2,4-hexadiyn-1,6-diol:

[A] Urethane (--OCONH--) derivatives, R'CH₂ --C.tbd.C--C.tbd.C--CH₂ R',including:

Hexyl Urethane: 166, R'=OCONH(CH₂)₅ CH₃

Pentyl Urethane: 155, R'=OCONH(CH₂)₄ CH₃

Butyl Urethane: 144, R'=OCONH(CH₂)₃ CH₃

Ethyl Urethane: 122, R'=OCONHCH₂ CH₃

Methyl Urethane: 111, R'=OCONHCH₃

[B] Ester (--OCO--) derivatives, R"'CH₂ --C.tbd.C--C.tbd.C--CH₂ R"',including:

Butyl Ester: 144E, R"'=OCO(CH₂)₃ CH₃

Ethyl Ester: 122E, R"'=OCOCH₂ CH₃

Methyl Ester: 111E, R"'=OCOCH₃

[C] Asymmetrical diacetylenes including:

156: R'--C.tbd.C--C.tbd.C--R",

where R'=CH₂ OCONH(CH₂)₅ CH₃

and R"=CH₂ OCONH(CH₂)₄ CH₃ ].

[D]Cocrystallized mixtures including:

Containing 80 weight percent or above of 166

85:15 mixture of 166 and 156

90:10 mixture of 166 and 156

and 4:1 mixture (TP41) of tricosadiynoic acid and pentacosadiynoic acid.

The urethane derivatives can be prepared by reacting e.g.,2,4-hexadiyn-1,6-diol with appropriate isocyanates (e.g.hexylisocyanate)in a solvent, such as tetrahydrofuran, using catalysts,such as di-t-butyltin bis(2-ethylhexanoate) and triethylamine asindicated below: ##STR1##

Ester derivatives can be prepared by reacting e.g.,2,4-hexadiyn-1,6-diol with appropriate acid chlorides in a solvent, suchas dichloromethane, using a base, such as pyridine as the catalyst;i.e., ##STR2##

Asymmetrical diacetylenes can be prepared by the Cadiot-Chodkiewicz typereaction methods. Some properties of some asymmetrical urethanederivatives of 2,4-Hexadiyn-1,6-Diol are given below in Table 1.

    __________________________________________________________________________    Compound                    M.P. Color Upon                                   Code  Structure             (°C.)                                                                       UV irradiation                               __________________________________________________________________________    156   C.sub.5 H.sub.11 NHCO.sub.2 CH.sub.2 (C.tbd.C).sub.2 CH.sub.2                 O.sub.2 CNHC.sub.6 H.sub.11                                                                         84-85                                                                              Red                                          167   C.sub.6 H.sub.13 NHCO.sub.2 CH.sub.2 (C.tbd.C).sub.2 CH.sub.2                 O.sub.2 CNHC.sub.7 H.sub.15                                                                         79.5-80.5                                                                          Blue                                         157   C.sub.5 H.sub.11 NHCO.sub.2 CH.sub.2 (C.tbd.C).sub.2 CH.sub.2                 O.sub.2 CNHC.sub.7 H.sub.15                                                                         62-64                                                                              Red                                          __________________________________________________________________________

Several urethane derivatives of (1) 2,4-Hexadiyn-1,6-Diol, (2)3,5-octadiyn-1,8-diol, [HO(CH₂)₂ --C.tbd.C--C.tbd.C--(CF₂)₂ OH], (3)4,6-decadiyn-1,10-diol, [HO(CH₂)₃ --C.tbd.C--C.tbd.C--(CH₂)₃ OH], and(4) 5,12-dodecadiyn-1,12-diol, [HO(CH₂)₄ --C.tbd.C--C.tbd.C--(CH₂)₄ OH],were also prepared and cocrystallized to increase the reactivity of theother diacetylenes.

A preferred diacetylene for the invention film device is 166[R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₅ CH₃ ] because it hasthe following desirable properties:

1. It crystallizes into a highly reactive phase from a number of commonsolvents.

2. It has low thermal reactivity.

3. It partially polymerizes to a red color when irradiated with amoderate dose, e.g., up to 100 rads of ionizing radiation.

4. Upon heating near or above its melting point (85° C.), the red colorchanges to a permanent blue/black. A blue, gray, or black color isdesirable for certain applications, such as diagnostic X-ray film.

5. It crystallizes into an inactive phase from its melt. The inactivephase has very little thermal and radiation reactivities. This propertyis especially useful in fixing the film thermally in a clean,nonpolluting, quick and rapid manner.

Though individual diacetylenes can be used, it is desirable to alter thereactivity of diacetylenes by cocrystallization. Cocrystallization canbe achieved by dissolving two or more diacetylenes, preferablyconjugated, prior to coating. As given in example 5, when TC and PC areco-crystallized, the resulting cocrystallized diacetylene mixture, suchas TP41 (4:1 mixture of TC:PC) has a lower melting point andsignificantly higher radiation reactivity. The reactivity can also bevaried by partial neutralization of diacetylenes having --COOH and --NH₂functionalities by adding a base, e.g. NaOH, or an acid, e.g. HCl,respectively.

In order to maximize radiation reactivity, 166 can be co-crystallizedwith other diacetylenes, e.g. 16PA, 155, 157, 154 and 156, which aredescribed above. Though certain diacetylenes, such as 155, increase thereactivity of 166, the partially polymerized cocrystallized diacetylenesprovide a red color upon melting. However, 156 increases the radiationreactivity of 166 and provides a blue color upon melting the partiallypolymerized diacetylene mixture. 166 can be cocrystallized withdifferent amounts of 156. Preferred is where the amount is 5-40 weightpercent of 156 to 166, most preferred are 90:10 and 85:15 respectiveweight ratios of 166:156. As used herein "9010" and "8515" refer tothese specific cocrystallized mixtures.

We have also discovered a new method for making asymmetrical derivativesof diacetylenes, such as 2,4-hexadiyn-1,6-diol. Asymmetricaldiacetylenes are generally synthesized by the asymmetrical couplingmethod (Cadiot-Chodkiewicz type reaction). However, it is a multistepprocess with poor yields. We have developed processes for synthesis ofasymmetrical diacetylenes which also provide the cocrystallized mixtureseither in one or two steps. In the preferred method, a difunctionaldiacetylene, e.g., a diacetylene-diol is reacted with one reactant,(e.g., an isocyanate) such that the molar ratio of the diol is in largeexcess to the minor isocyanate. For example, to prepare the 90:10mixture of 166:156, 5 mole percent of n-amyl isocyanate is added to the2,4-hexadiyn-1,6-diol in tetrahydrofuran (THF) solvent in the presenceof a tin catalyst, e.g. dibutyl tin bis(2-ethyl hexanoate) and atertiary amine, e.g. triethylamine. Following this, 95 mole percent ofn-hexyl isocyanate is added to the reaction mixture to complete thereaction to form the cocrystallized 90:10 mixture of 166:156 directly.

The procedure results in an almost quantitative yield for preparingmixtures of e.g., 166 and 156 in various proportions. The procedures forsynthesis of 9010 (a mixture containing 90% of 166 and 10% of 156) and8515 (a mixture containing 85% of 166 and 15% of 156) are given inExample 2 and Example 3, respectively. Using the procedures described inExamples 2 and 3, mixtures of 166 and 156 having different ratios wereprepared, and purified by crystallization. The properties of variouscocrystallized mixtures of 166:156 are given below in Table 2.

                  TABLE 2                                                         ______________________________________                                        Colors of Some Partially Polymerized Cocrystallized 166 and                   156 Before and After Melting.                                                 Code  Wt. Percent Color of Partially Polymerized Mixture                      Name  166     156     Before Melting                                                                            After Melting                               ______________________________________                                         166  100      0      Red         Blue                                        9505  95       5      Red         Blue                                        9010  90      10      Red         Blue/purple                                 8515  85      15      Red         Purple                                      8020  80      20      Red         Purple                                      7525  75      25      Red         Red/purple                                  7030  70      30      Red         Red                                         6040  60      40      Red         Red                                          156   0      100     Red         Red                                         ______________________________________                                    

All cocrystallized mixtures listed in Table 2 provided an inactive phaseupon melting. However, the color of the cocrystallized diacetyleneshaving more than 20% of 156 was red after fixing the film.

Other asymmetrical derivatives, including different functionalities,e.g., ester as one substituent and urethane as the other, can also beprepared. A procedure for synthesis of 90:10 mixture of 166 and 16PA isgiven in Example 4. Using the general procedures given in Examples 3, 4and 5, it is possible to prepare a variety of other asymmetricalderivatives and their mixtures for cocrystallization.

Polymers having diacetylene functionality [e.g., {--R'--(C.tbd.C)_(n)--R"--}_(x), where R' and R" can be the same or different diradical,such as --(CH₂)_(n) --, --OCONH--(CH₂)_(n) --NHCOO-- and --OCO(CH₂)_(n)OCO-- in their backbones are also preferred because of the fact thatthey are polymeric and do not require a binder.

The preferred diacetylenes are those which have a low (below about 150°C.) melting point and crystallize rapidly when cooled at a lowertemperature, e.g. room temperature.

Another class of preferred diacetylenic compounds are those having anincorporated metal atom and can be used as in-built convertor.Diacetylenes having functionalities, such as amines, ethers, urethanesand the like can form complexes with inorganic compounds. It is possibleto synthesize diacetylenes having an internal convertor which iscovalently bonded, such as boron and mercury, lithium, copper, cadmium,and other metal ions. For example, the --COOH functionality of TC, PCand TP41 can be neutralized with lithium ion and synthesis ofR--C.tbd.C--C.tbd.C--Hg--C.tbd.C--C.tbd.C--R is reported (M. Steinbachand G. Wegner, Makromol. Chem., 178, 1671 (1977)). The metal atom, suchas mercury atom thereby incorporated into the diacetylene can emit shortwavelength irradiation upon irradiation with photons and electrons. Thefollowing are some representative examples of preferredconvertor-diacetylenes:

[A] R--C.tbd.C--C.tbd.C--Hg--C.tbd.C--C.tbd.C--R, where R is analiphatic or aromatic radical.

[B] {--C.tbd.C--C.tbd.C--(CH₂)_(n) --C.tbd.C--C.tbd.C--Hg--}x, where n=1to 20 and x is higher than 2.

[C] M--OOC--(CH₂)_(n) --C.tbd.C--C.tbd.C--(CH₂)_(n) --COOM, andM--OOC--(CH₂)_(n) --C.tbd.C--C.tbd.C--Hg--C.tbd.C--C.tbd.C--(CH₂)_(n)--COOM, where M is a metal ion, such as Hg, Ag, Cu, Fe, and Li.

D] A--(CH₂)_(n) --C.tbd.C--C.tbd.C--(CH₂)_(n) --A, where A is an amineor ether complexed with an inorganic compound.

A radiation sensitive layer can be prepared by making an emulsion ofdiacetylene complexed with a convertor using a polymeric bindercomplexed with a convertor. This type of coating can be more sensitiveto radiation and hence a significantly more intense image can beobtained, as both diacetylenes and the binder have convertors.

For certain applications, such as diagnostic X-ray imaging, it isdesirable to have a black image. Most diacetylenes partially polymerizeto either a blue or red color. A small number of diacetylenes, such as2CU (R=--(CH₂)₂ OCONH-- cyclohexyl) partially polymerize to a yellowcolor. Some blue colored partially polymerized diacetylenes (e.g. 4BCMU,R=--(CH₂)₄ OCONHCH₂ COO(CH₂)₄ H) change to a red color while others(e.g., 3ECMU, R=--(CH₂)₃ OCONHCH₂ COO(CH₂)₄ H) retain their blue colorupon heating. Many red colored partially polymerized diacetylenes, suchas 144, remain red upon heating. In order to obtain a black color, onecan use a mixture of diacetylenes including 166, in appropriate amountsto produce a black color which absorbs over a wider range of the visibleregion. A radiation sensitive layer containing more than one diacetyleneparticularly in cocrystallized form, to obtain the desired color is alsopreferred.

The following terminologies are used for defining the reactivity(polymerizability) of a diacetylene. The polymerizable form of adiacetylene(s) is referred to as "active". If a diacetylene ispolymerizable with radiation having energy higher than 4 eV, wavelengthshorter than 300 nm, then it is referred to as "radiation active". If itis polymerizable upon thermal annealing then it is referred to as"thermally active". A form of diacetylene which displays little or nopolymerization is referred to as "inactive". If it displays littlepolymerization with radiation (having energy higher than 4 eV) then itis referred to as "radiation inactive" and if it is significantlynonpolymerizable upon thermal annealing, then it is referred to as"thermally inactive". Diacetylenes having reactivity/polymerizabilitycharacteristics in between these definitions are referred to as"moderately active". The most preferred form of diacetylene is one whichis highly radiation reactive and displays little or no thermalreactivity. However, diacetylenes which are radiation active alsousually have some thermal reactivity. Hence, the preferred form ofdiacetylene is one which is highly to moderately radiation active withlittle or no thermal reactivity. Thermal reactivity can be decreased andradiation reactivity can be increased by cocrystallization and molecularcomplexation. As an alternative, the film can be stored at lowertemperature to slow down the thermal reactivity. Alternatively, thediacetylene can be prepared in a radiation inactive form and activatedto the active form prior to use by contacting with an organic solvent.

Though diacetylenes are the most preferred radiation sensitivematerials, other radiation sensitive materials can also be used formaking the film device using the procedure and formulations describedhere. In addition to silver halides and mixtures thereof, ferric salts,potassium dichromate, aromatic diazo compounds, polycondensates ofdiazonium salts, the naphthoquinone diazides, photopolymers andphotoconductive materials, silver molybdate, silver titanate, silvermercaptide, silver benzoate, silver oxalate, mercury oxalate, ironoxalate, iron chloride, potassium dichromate, copper chloride, copperacetate, thallium halides, lead iodide, lithium niobate, and mixturesthereof are also preferred s radiation sensitive compositions for makingthe film device using the convertors, the binders complexed withconvertors and the processes of making the film emulsions describedherein. The image of the film containing nondiacetylenic radiationsensitive compounds can be amplified by incorporating a convertor in theunder coat, radiation sensitive coat and top coat, which emits radiationto which the said compounds are sensitive upon irradiation with higherenergy radiation.

An opaque film can be used. However, it is desirable that the opaquefilm can become substantially transparent after processing, i.e.,fixing. Several techniques, such as grinding the crystals into very fineparticles and crystallizing diacetylenes into very fine particles canprovide a transparent coating. A transparent film will provide a clearimage with high resolution. For certain applications, a transparentcoating is desirable but not required. As diacetylenes polymerize onlyin the solid (crystalline) state, they must be in the crystalline statein the binder. For clarity of the film, the binder for the diacetyleneshould be highly transparent. However, in order to avoid scattering andhence opacity, the preferred crystal size of the diacetylene is smallerthan 300 nm, preferably less than 100 nm (1 micron). In order to obtaina transparent film, the refractive indices of the diacetylene and thebinder should also be as close together as possible. The refractiveindex of organic materials is usually low and within a narrow range.Amorphous polymers are desirable but semi-crystalline polymers can beused as binders if they provide a significantly transparent coating. Acrystalline polymer can be made amorphous by cross linking. Binderswhich wet the surface of the diacetylene crystals will also providehigher transparency. A wetting agent or surfactant can increase thewetting of the crystals by the binder. A binder which is transparent andhas a refractive index close to that of diacetylene and/or preferablywets the diacetylene crystal surface. A coating or a film is consideredtransparent if over about 25% of the incident light is transmittedthrough the film. A film is considered opaque if more than about 75% ofthe light is absorbed, reflected or scattered rather than beingtransmitted through. A colored film can also be transparent at onewavelength of incident radiation if that light is not absorbed orpartially absorbed. However, the same colored film can appear opaque toa different wavelength of incident radiation, if its color absorbs theincident radiation. The film of Example 22 has 70% transparency asdescribed. In general, transparency, used as herein, is the measuredtransparency of the film to visible radiation prior to use.

The term "convertor(s)" is used for any material, substance, mixture,which can be complexed or doped with other substances, which whenirradiated with high energy radiations, both ionizing and nonionizing,produces relatively lower energy radiation, either of the same ordifferent type, via any process including scattering, attenuation,fluorescence, phosphorescence, and conversion. Inorganic andorganometallic compounds are preferred as convertors because they havethe ability to transfer/convert high energy radiation into lower energyradiation via many processes, such as scattering, absorbance,fluorescence, and phosphorescence. The selection of a convertor dependsupon the type of radiation to be monitored and its energy. For example,lead and barium salts are good convertors for monitoring X-ray radiationand boron, lithium salts are good convertors for measuring thermalneutrons.

When high energy radiation strikes a metal, .secondary electrons andother radiations of longer wavelengths are emitted. The emission ofthese secondary radiations become greater in materials with a highatomic number. Barium salts are especially preferred because they arenontoxic. Elements having high atomic number (Z), such as lead, are alsopreferred. Other convertors include alloys, salts, and free metals ofzinc, tin, silver, tungsten, molybdenum, platinum, gold, copper, iodine,and bromine.

In general, it is not necessary for a binder to form a complex withmetal salts. Preformed metal complexes can also be used as convertors.In addition, metal complexes and salts (ionic and co-ordinationcomplexes including those forming hydrogen bonds) of ethylenediamine,porphines, crown ethers (e.g., cryptates), polyphosphates(hexametaphosphoric acid), aminocarboxylic acids (e.g., EDTA),1,3-diketones (acetylacetone), hydroxycarboxylic acids (e.g., citricacid), aminoalcohols (e.g., triethanolamine), phenols (e.g.,salicylaldehyde and chromotropic acid), aminophenols (e.g.,oxinesulfonic acid), oximes (e.g., dimethylglyoxime), Schiff bases(e.g., disalicyladehyde 1,2-propylenediimine), sulfur compounds (e.g.,toluenedithiol and thioglyconic acid) can be added to a binder to beused as a convertor combination as long they form an essentially clearcoating. Polymer having these functionalities can be used as binders.However, it is not necessary to have a clear coating for the screen andfor certain applications, especially if the coatings are on an opaquesubstrate, such as paper and skin. The process of mixing a finelydivided convertor into a binder is given in Example 13. Instead ofcolloidal silica, a person skill in the art can also mix fine particles,prefereably, smaller than 500 nm, of other convertor materials, e.g.,pyrophosphates of hafnium, germanium, zirconium, silicon and mixturethereof, into a binder and homogenize with a radiation sensitivematerial, such as a diacetylene to make the emulsion.

"Mix complexes", i.e., two or more metals complexed with one binder or amixture of two polymers complexed with one metal, forming differenttypes of complexes, can also be utilized. The ratio of metal to bindercan be varied to additionally form phosphor materials.

The resulting image can be amplified by incorporating convertormaterials into the radiation sensitive coat, under coat, top coat, andpreferably into all three. The convertors will absorb high energy X-ray,radiation, electrons, and neutrons and convert the absorbed radiationinto secondary low energy ionizing radiation. These secondary low energyionizing radiations and nuclear particles, such as alpha particlesemitted by the convertor can initiate polymerization of diacetylene. Thesecondary radiation, irrespective of its source can be absorbed by theconvertor materials and emit tertiary ionizing radiation which in turncan also initiate polymerization of diacetylenes. When the secondaryradiations are electrons, use of electroluminescence materials asconvertors can amplify the image.

The image can be further amplified by placing the film into intimatecontact with one or two screens made from convertor materials. Thescreens in their simplest form can be a plain metal foil and/or coatedwith a radioluminescence, electron luminescence or fluorescence phosphormaterial, which emits radiation of usually lower energy. We haveobserved that by placing the diacetylene film of Example 22 in closecontact with (1) metal screens for converting megavolt radiations and(2) coatings made from the convertor materials of Tables 3 and 9, theimage can be amplified several fold. The X-ray image can be amplified byusing phosphor materials which emit energy higher than 4 eV as thescreen materials. Phosphor materials which emit long wavelength UV lightcan be made to emit higher energy radiation by appropriate dopants,quantity of dopants and doping processes. An appropriate voltage canalso be applied to the screens to produce secondary electrons which inturn can also initiate polymerization of diacetylenes, thereby alsoamplifying the image.

The nature of the desired convertor material used will depend upon thenature and energy of the incident radiation. To increase the contrastand response of the film, metal screens can be placed in direct contactwith the film during the exposure to photons, and electrons of megavoltenergy. The first screen can be thinner to prevent attenuation of theradiation while the second screen can be thicker. The first metal screencan also preferentially absorb scattered radiation and hence improve thecontrast of the image. Secondary electrons are ejected from the metal bythe radiation. Both absorption of scattered radiation and emission ofsecondary electrons becomes greater in materials with a high atomicnumber. Materials selected from the group consisting of Cr, Mn, Fe, Co,Ni, Zn, Zr, Mo, Ru, Pd, Ag, Cd, In, Sn, Sb, Ba, W, Pt, Hg, Bi, Pb,uranium, lanthanides and their mixtures and alloys can be used as theactive material in an intensifying screen for imaging with X-rays, gammarays or electrons. Lead (Pb) is a preferred metal for this purpose.

When high energy radiation, such as X-ray radiation of lower energy,e.g., lower than 1 MeV, becomes incident on certain substances, light isemitted (luminescence). The commercially available intensifying screensfor diagnostic x-rays (10-200 KeV) produce white light. Silver halidefilm is sensitive to white light. Silver halide film is comparativelyless sensitive to X-ray radiation. The diagnostic X-ray image isintensified by using an intensifying screen, such as those coated withzinc sulfide, barium lead sulfide, or calcium tungstate. The image onthe silver halide film is intensified by as much as three orders ofmagnitude with these screens.

Any material, which is an organic, inorganic and/or organometalliccompound, which emits radiation of wavelength lower than 300 nm, (energyhigher than 4 eV) including those emitted by fluorescence andphosphorescence, upon irradiation with high energy radiation can be usedas a convertor for the undercoat, radiation sensitive coat, top coat andthe screens. In order to maximize the sensitivity of the film, theselection of a proper convertor is required. A convertor which has ahigh ability to absorb high energy radiation and emit high intensityradiation of significantly lower energy, but higher than 4 eV, ispreferred.

In order to maximize the darkness of the image, the convertors shouldpreferably be complexed with the binder. For example, lead and bariumsalts, e.g., lead iodide and barium iodide, form complexes withpolyethyleneimine, PEl. However, lead is considered toxic. Thus, theelement having a high atomic number which is nontoxic and inexpensive isbarium. Additionally, PEl also forms complexes with several bariumsalts, such as barium iodide and barium sulfate. Complexes of PEl withmetal iodides are preferred over other salts, e.g. chlorides, because ofthe high atomic number of iodine. The list of complexes of PEl areincluded below in Table 3.

                  TABLE 3                                                         ______________________________________                                        Properties of Complexes of PEI with Some Inorganic                            Compounds.                                                                            Concentrations    Nature                                              Convertor PEI         Convertor   of the film                                 ______________________________________                                        Phosphoric acid                                                                         10     ml 30%   5.0  ml 85% Tacky                                   Sulfuric acid                                                                           30     ml 10%   1.5  ml     Tacky, Acidic                           Hydrochloric                                                                            20     ml 30%   13.0 ml     Tacky, Acidic                           acid                                                                          Hydroiodic acid                                                                         10     ml 30%   13.3 ml     Tacky, turns                                                                  yellow                                  Zinc sulfate                                                                            100    ml 7.5%  7.0  g      Non-tacky                               Zinc iodide                                                                             10     g 30%    2.5  g      Non-tacky                               Barium iodide                                                                           10     g 30%    1.5  g      Non-tacky                               Sodium iodide                                                                           10     g 30%    5.0  g      Tacky                                   Zinc oxide                                                                              60     ml 10%   0.6  g      Tacky                                   Cesium bromide                                                                          100    ml 7.5%  3.0  g      Tacky                                   Cesium iodide                                                                           10     ml 7.5%  4.0  g      Tacky                                   Lead iodide                                                                             30     ml 10%   2.8  g      Non-tacky                               Barium bromide                                                                          60     ml 10%   3.0  g      Non-tacky                               ______________________________________                                    

Substances commonly known as cathode/electro luminescence materials,i.e., are materials which when contacted with electrons emit lowerenergy radiation. Electroluminescence phosphors, such as hafniumpyrophosphate and those substituted with zirconium, germanium andsilicon, which emit UV light or can me made to emit UV light by dopingare preferred phosphors. These materials can also be used as convertorsif they emit radiation having energy higher than 4 eV, because thesecondary electrons can induce cathode luminescence materials to emit UVand X-ray radiation which can initiate polymerization of diacetylenes.

A material which emits radiation having a wavelength shorter than 1 nmcan be used as a convertor. Preferred are those which emit UV radiationin the range of 300 to 1 nm. UV radiation is rapidly absorbed by thediacetylene functionality and causes their polymerization. Hence, apreferred convertor should emit radiation of energy between 300 and 100nm. Materials commonly known as phosphors include those from the II-VIIPeriodic Table group phosphors (e.g. ZnS, ZnCdS) and a rare earthphosphor (e.g. Gd₂ O₂ S, Y₂ O₂ S) and three elemental oxide phosphors(e.g. CaWO₃, ZnSiO₄). Convertors, such as barium lead sulfate,naphthalene-sodium iodide doped with Tl, ZrP₂ O₇ (zirconium phosphate)which can emit UV light can be used. Properly doped phosphors, such asbarium fluorochloride and lanthanum oxybromide, terbium activated rareearth oxysulfide (X₂ O₂ S where X is gadolinium, lanthanum or yttrium),GdOS:Tb(lll), LaOS:Tb(lll), LaOBr:Tb(lll), LaOBr:Tm(lll), Ba(FCl)₂:Eu(ll), SrB₄ O₇ :Eu (stronsium europium borates), BaSi₂ O₅ :Pb (bariumsilicate), (CeBa)MgAl₁₁ O₁₉ (cerium, bariummagnesium aluminate),strontium pyrophosphate activated with europium, and phosphates ofzirconium, germanlure, silicon and hafnium can emit short wavelength UVlight. The preferred phosphor is the one which emits short wavelength UVlight (e.g., 300-50 nm).

For monitoring neutrons, compounds having a high neutron cross sectionare preferred convertors. The neutron cross section for boron decreasesas the energy of neutrons increases. Naturally occurring boron compoundshave about 20% boron-10. PEl forms a complex with boric acid. Boric acid(BA)is nontoxic and inexpensive. BA has only 5% solubility in water.However, PEl can form up to 1:2 molar complexes with BA. Higherconcentrations of BA makes the film brittle and lower concentrations ofboric acid keeps the film tacky. The optimum molar ratio of PEl:BA isabout 1:1. The complex of PEl with BA is referred to as PEl/BA. Webelieve that PEl forms a complex with boric acid. However, it can be aneutral salt of a very weak acid (boric acid), with a relatively strongbase (PEl). Films containing boron and lithium, especially boron, as aconvertor can be used for monitoring thermal neutrons and boron-neutroncapture therapy. Elements having high neutron cross section and emittingelectrons and gamma rays, e.g., gadolinium, can also be used asconvertor for neutrons.

The convertor can be mixed with the diacetylene in the radiationsensitive layer and/or with the under coat and the top coat. Diacetyleneparticles can be coated on the convertor or vice versa. The diacetylenelayer can also be sandwiched between two layers of convertors. In orderto avoid or minimize internal absorption (absorption by the convertoritself) of the emitted secondary radiation, which are responsible forpolymerization of diacetylenes, the convertor should be very thin andtransparent. The binder should be significantly transparent to thesecondary radiation emitted by the convertor. For example, the complexesof PEl in Table 3 are transparent to UV light except that of leadiodide.

Although any solid substrate having a smooth surface can be used, apreferred substrate is a flexible and transparent plastic film. Plasticfilms, such as polyethylene, polypropylene, polyvinylchloride,polymethylmethacrylate, polyurethanes, nylons, polyesters,polycarbonates, polyvinylacetate, cellophane and esters of cellulose canbe used as the transparent substrate. The most preferred substrates arethe 15-300 microns thick films of polyethylene terephthalate,polycarbonate (polycarbonate of bisphenol-A), cellulose acetate andpoly(vinylacetate) having high transparency (higher than 60%) and gooddimensional stability. A paper, e.g., photographic paper, can also beused as a substrate. Metal foils, such as aluminum can be used.Depending upon the utility, the substrate can be any surface, includinghuman skin, when the coating material is in form of an applied lotion orcream.

Strong adhesion of the radiation sensitive layer with the substrate filmis essential. If the coating does not adhere to the base film, itusually flakes off. The adhesion of PEl/BA with polyester film isgenerally very poor. The coating often flakes off when the film is bent.In order to increase the adhesion of the coating to the substrate, athin coating, known as a subcoating, undercoat or substratum, which hasability to bond with substrate, such as polyester base film and theradiation sensitive coating, is applied on the polyester film. Thenature/composition of the substratum will depend upon thenature/composition of the binder. For example, when gelatin is used asthe binder, the substratum layer for polyester (e.g. Mylar) can becomposed of cellulose ester (e.g. cellulose acetate) and gelatin in awater/acetone solution.

In order to increase the bonding of PEl/BA with polyester film, severalsubstratum formulations were developed. The molar ratio of PEl:BA usedis usually 1. However, if the molar ratio of PEl to BA is more than 1,e.g., 1.1, with a slight excess of PEl, the coating providessatisfactory adhesion. However, higher concentrations of PEl makes thecoating moisture sensitive and on a hot and humid day the coating willdevelop a slight tackiness.

Other substratum formulations can contain two polymers, one polymerproviding bonding with the substrate while the other provides bondingwith the radiation sensitive coat. The substratum coating can be about afew microns thick. The following formulations provided satisfactorysubstratum coatings: polyvinylacetate plus Gelatin, PEl pluspolyvinylpyrrolidone (PVP), and polyvinylpyrrolidone pluspolyvinylacetate. Polymers, such as polyvinylacetate form a strong bondwith Mylar® while the water soluble polymers e.g. PVP, form a bond withPEl/BA. A representative substratum formulation which providessatisfactory adhesion with Mylar® and PEl/BA is given below.

A preferred formulation for the substratum is provided in Example 10.Nine parts of 10% polyvinylacetate in ethanol:water (4:1) were mixedwith 1 part of 10% low molecular weight polyacrylic acid in ethanol. Themolecular weight of polyacrylic acid was 2,000. Polyvinylacetate bondedwith Mylar® while polyacrylic acid bonded with PEl/BA. Polyacrylic acidformed a bond with PEl/BA acid because the acid functionality (--COOH)of polyacrylic acid can form a bond with the amine functionality(--NH--) of polyethyleneimine.

The preferred substratum formulation can contain a convertor, such aslead iodide, barium iodide, zinc sulfate and sodium iodide or a phosphormaterial which is capable of producing radiation of lower energy whenirradiated with the high energy radiation thereby enhancing the image asshown in Example 31.

Strong adhesion of the radiation sensitive coat is not required when thecoating material is in form of an applied lotion or cream which can bewiped off the surface, e.g., skin, after irradiation.

Different polymeric materials are constantly being searched for in aneffort to find one which can incorporate a sufficient quantity ofconverter material to produce a transparent film which will amplify theimage produced by the diacetylene when exposed to high energy radiation.A binder is a polymeric or nonpolymeric, organic or inorganic, includingorganometallic, material which embed the radiation sensitive materials,such as diacetylene and silver halide. Any polymeric material which hasthe ability to form a transparent coating, preferably forming a complexor dissolving an inorganic compound (e.g., to form a solid solution) canbe used as a binder for the radiation sensitive material. We havedemonstrated that both water soluble and water insoluble polymers can beused as the binder. A mixture of two or more solids is referred toherein as a solid solution, if (1) one of the solids of the mixture hasnot crystallized or precipitated out as a separate phase, (2) themixture precipitates as a highly amorphous solid, or (3) fine particlesof one solid in the mixture are covered with the other solid whensolidified from their solution or melt, to minimize the scattering ofthe incident light. Since the scattering of the light will be minimum,the coating of a solid solution will appear significantly transparent..The coatings of the solid solutions When a water insoluble polymer isused as the binder in a nonaqueous system, organometallic compounds andcomplexes can be added as convertors. For the water soluble polymers,inorganic compounds, which either form a complex, e.g. a Lewis acid-basepair, or a solid solution as described above with the binder, can beadded to a polymeric solution. Polymers having the followingfunctionalities can be used as water soluble binders:

1. Polyacids: Polyacrylic acid.

2. Polyamines: Polyethylene amine, polyvinyl pyridine,polyethyleneimine.

3. Polyethers: Polyethylene oxide and polyvinylethers.

4. Polyalcohol: Polyvinylalcohol.

5. Polyamide: Polyacrylamide.

6. Gelatin

A number of water soluble polymers, such as gelatin, polyethylene oxide,polyacrylic acid, polyvinylalcohol, polyvinylpyrrolidone,polyvinylpyridine, polyacrylamide, and polyethyleneimine were tried asthe binders. Although a wide variety of polymers can be used as a binderfor the radiation sensitive material, the preferred polymer should havethe capability of forming a complex or solid solution with theconvertor. Polyethyleneimine, (--CH₂ --CH₂ --NH--)_(n), is a preferredbinder because of the following reasons:

1. It complexes with a large number of inorganic compounds, which can beused as convertors, e.g., boric acid and barium sulfate, to form watersoluble complexes.

2. Even though PEl is tacky and hygroscopic, some of the complexes arenontacky and significantly less hygroscopic.

3. The water soluble complexes of PEl provide a highly transparentcoating.

4. Highly stable emulsions of diacetylenes can be prepared in solutionsof the complexes.

5. The emulsions prepared in solutions of the complexes have a highradiation reactivity and very little thermal reactivity.

6. PEl is considered nontoxic. It is used industrially for waste watertreatment.

In order to alter the binder properties, such as water solubility, PElcan be crosslinked with crosslinking agents, such as diisocyanates,diacid chlorides, and aldehydes. We crosslink PEl with glutaraldehyde.PEl of higher molecular weight, 10,000 to 5,000,000 is preferred. Apreferred concentration of PEl in the film emulsion is 5-30%, the mostpreferred is 10-20%. Higher molecular weight binders will provide higherviscosity. We have observed that size of the crystals decreases withincrease in viscosity of the binder solution.

When a polymer forms a complex with an inorganic material, it oftenbecomes brittle. For example, PEl is an adhesive. However, a 1:1 molarmole complex of PEl/BA is slightly brittle. The binder convertorcomposition should be flexible so that it does not crack when the filmis bent. Plasticization of the binders will depend upon their chemicalstructure. A chemical which is a good plasticizer for one plastic maynot be a useful plasticizer for another. For complexes of PEl, preferredplasticizers are paraffinic acids, such as heptanoic acid, hexanoicacid, palmitic acid, oleic acid, and propionic acid. The plasticizerscan also be chemically bonded with PEl by reacting PEl with a fattychain isocyanate and acid chloride. Plasticized PEl is significantlyless sensitive to moisture.

Many water insoluble polymers are known to form complexes withorganometallic compounds (Organometallic Polymers, C. E. Carraher Jr.,J. E. Sheets, and C. U. Pittman, Jr. (Editors), Academic Press, NY 1978;Metallorganic Polymers, K. A. Andrianov, Interscience Publishers, NY1965, Polymer-metal complexes; M. Kaneko and Elshun Tsuchida, J. Polym.Sci., Macromolecular Reviews, 16, 397, 1980). Conductive polymers, suchas polyacetylene, polythiophenes, polyquiniline, and polyaniline whencomplexed/doped with metal salts, such as arsenic pentafluoride,bromine, iodine can also be used polymeric convertors. Inorganicpolymers, such as poly(phosphazenes), polysiloxanes andpoly(metallo-siloxanes), poly(carborane-siloxanes), poly(sulfurnitride), poly(metal phosphenates) can also be used as polymericconvertors.

Gelatin, the most widely used binder for radiation sensitive materials,has many desirable properties, such as high solubility in water aboveabout 50° C. and the ability to gel or swell below 45° C. for wetprocessing of the exposed film. Many of these properties are notrequired if the processing of the film is dry. A large number of binderscan be used if the processing, e.g., developing and fixing of the film,is a dry process. Gelatin complexed or in form of solid solution withconvertor is a also a preferred binder.

If the binder has the ability to form a complex or solid solution, onecan use higher concentrations of the radiation absorbing materialincluding fluorescent and convertor materials. Gelatin is a poorcomplexing agent. It is also poor in forming solid solutions withinorganic materials. However, we have found that as shown in Example 11,gelatin can also form complexes or solid solutions with inorganiccompounds. Complexed gelatin or solid solutions of gelatin withconvertors is a preferred binder system.

The binder polymers can be homopolymers, copolymers, graftcopolymers,block copolymers, polymeric alloys and mixtures thereof.

A top coat of about 0.5-2 microns, also known as a supercoat, is usuallyapplied to make the coating resistant to abrasion. The top coat cancontain a convertor, such lead iodide and sodium iodide which is capableof producing radiation of lower energy when irradiated with the highenergy radiation thereby enhancing the image. Enhancement of the imageby incorporating a convertor in the top coat is shown in Example 30.Although the polymers in the radiation sensitive coat, sub-coat, and topcoat can be different, the convertor material can be the same ordifferent depending upon the binder used. Gelatin is widely used as theprotective coat. Other polymers which can provide scratch resistantcoating can also be used as protective coat. As the film does notrequire wet processing, any scratch resistant polymers can also be usedas the top coat. As an alternative to gelatin, we top coated the filmwith polyisobutylmethacrylate from cyclohexane solution. Cyclohexane isa nonsolvent for most diacetylenes and hence does not affect thereactivity or the nature of the crystals. Polyisobutylmethacrylateprovides a very hard coating. The protective coat can also contain aconvertor material, a low molecular weight UV absorbing compound, andother additives, such as an antistatic compound.

The PEl/BA/diacetylene coating can be top coated with a water solublepolymer, such as gelatin and polyvinylpyrrolidone. Gelatin provides asatisfactory top coat. Gelatin dissolves in water only above about 30°C. A five percent solution of gelatin is applied to the coating ofPEl/BA/9010 at about 40° C. using a wire wound rod. Gelatin solution candissolve PEl/BA but does not dissolve the crystals of the diacetylene.The bonding of gelatin with PEl/BA is excellent, i.e., it passes thecross-hatch test and the coating is scratch resistant.

If the top coat contains additives, such as a convertor, a scratchresistant protective coat can be applied on the top coat. This top coatcan be gelatin without a convertor. Gelatin is preferred but anypolymeric material, such as one of the polyurethanes, polyepoxy, andpolyacrylics, which provides hard protective coat can also be used.

The diacetylene film will generally not require protection from whitelight and hence a black/opaque protective envelope is not essential forits storage and handling. However, as diacetylenes are sensitive toshort wavelength UV light, the films preferably should be stored in a UVabsorbing film envelope, such as Mylar® or Llumar®, to protect it fromambient UV light and air pollutants. In order to protect the film fromshort wavelength UV light, the coating of PEl/BA/9010 is also coatedwith gelatin containing a UV absorber, such as maleic acid, sodiumsalicylate, benzophenone, or benzophenone tetracarboxylate. These arethe conventional UV absorbers used in sun-tan lotions.

A blue film of 4BCMU in polyethyleneoxide irradiated with 100 radappears substantially darker when viewed with red light andsubstantially lighter when viewed with green light. The red film appearsmuch darker when viewed with green light. When viewed with white light,the diacetylene film appears lighter because it does not absorb bluelight of the visible region. However, silver halide film absorbs overthe entire visible region. Hence, use of an appropriate light will makethe image appear much darker. Alternatively, a mixture of appropriatediacetylenes and dyes can provide a dark/black image upon irradiation.Addition of appropriate dyes and viewing of the film with appropriatecolor filter or color light is preferred.

Upon irradiation, the diacetylene(s) will polymerize to a noticeable,visible color. A film of Example 22 was irradiated with differentdosages of 60 KeV X-ray, gamma rays from cobalt-60, 10 MeV X-rays, 12MeV electrons, and 20 MeV neutrons at different dosages. Optical densityand visible spectra were recorded. As shown in FIGS. 3 and 4 theradiation dose can be accurately determined with a spectrophotometer. Adensitometer can be used for the determination of optical density and aquick estimate of radiation dose. A scanning densitometer can also beused to prepare dose distribution curves effectively. Appropriate colorfilters can be used.

The digital imaging technology can be used for enhancement of theimages. Most of these systems digitize the film via high quality, lownoise video camera, or laser scanning techniques and process the datawith a specialized graphic processor or a digital imaging computer.

The diacetylenic film is a self-developing device, i.e., it develops itsown color while being irradiated. However, after the exposure, the filmrequires deactivation (fixing) of the developed image by making theunreacted molecules inactive. If, after the exposure, the diacetylene isnot deactivated, the unreacted molecules will undergo slow thermalpolymerization during the storage or unintended exposure to ionizingradiation. There are several ways a diacetylene film can be fixed: (1)by extraction of the unreacted monomer molecules with a nontoxicsolvent, such as ethanol, (2) by selective destruction of conjugatedtriple bonds, with a chemical agent, such hydroxylamine, (3) byselective reaction of the functionalities of the side groups, such asester, thereby making the diacetylene inactive, (4) by isomerization ofthe conjugated triple bonds, (5) forming a complex with diacetylene orchemical functionality of the side group, e.g., via hydrogen bonding,(6) making diacetylenes inactive, and (6) by combination of two or moreof the above methods.

Diacetylenes having functionality which can be chemically or physicallyconverted to another functionality or form which providesnonpolymerizable form is also a preferred process for fixing the film.Diacetylenes, such as 4BCMU, TC, PC and TP41 can also be permanentlyfixed with a base, such as sodium hydroxide and sodium carbonate. Whenblue films of 4BCMU and TP41 are dipped in either a 5% solution ofsodium hydroxide or 30% solution of sodium carbonate, they permanentlychange to red color in about five minutes at room temperature. Thehydrolyzed (in case of 4BCMU) and neutralized (in case of TC, PC andTP41) unreacted molecules become inactive to both high energy radiationand temperature. The fixing of the diacetylenic film can be done underambient light. Chemical fixing with compounds which react or complexwith diacetylene or the side group functionalities is a preferredprocess of fixing the film.

One of the effective fixing solutions for the diacetylene film can be asolution of a base, such as sodium hydroxide, in a solvent system, suchas aqueous ethanol. As ethanol is a nonsolvent for gelatin it willprevent excessive swelling. Ethanol will extract unreacted monomer outof the swollen binder and facilitate the reaction of sodium hydroxidewith diacetylene. Sodium hydroxide will also make the monomer moleculesinactive (unpolymerizable) by isomerization of conjugated triple bondsto cumulene and hydrolysis of the ester and urethane functionalities ofthe side groups. The most preferred base for fixing the film are one ofthe alkali metal hydroxides, alkali metal carbonates and phosphates, andquaternary ammonium hydroxides. They include, sodium hydroxide,potassium hydroxide, sodium carbonate, potassium carbonate, potassiumphosphate, ammonium hydroxide, tetraethyl ammonium hydroxide anddibutylamine.

The most preferred solvent type fixing agents are water soluble of lowtoxicity, such as ethanol, acetone, isopropanol, tetrahydrofuran,dimethylformamide, dimethylsulfoxide, glyme and glycerol.

The image can be further amplified and made darker and absorbing in theregions of visible spectrum by making diacetylenes or the radiationpolymerized diacetylenes react/complex with reactants, such as dyes andindicators. The dye/indicator can react/complex with the backbone orside chains of polydiacetylene. The nature of the dye/indicator alsodepends upon functionality or nature of the side group ("R") of thediacetylenes. We have found that several dyes can be used for theamplification of the image. A red image of partially polymerized 4BCMUcan be made darker by dipping the image in a solution of alkali blue 6B.TC, PC and TP41 has --COOH functionality and it can react with a numberof carboxylic acid sensitive dyes, such as bromophenol blue. Apoly(TP41) chain has a number of --COOH functionality. Each --COOHfunctionality can react with a pH dye. Hence, poly(TP41) molecule willappear significantly more intense. Similarly, using proper indicators,dyes and complexing agents, one can substantially amplify the image.Dyes, such as Acid Blue 113, Fast Green FCF, Alphazurine A, Guinea GreenB, Erioglaucine, Pararosaniline Acetate, Pararosaniline Base, EthylViolet, Brilliant Blue G, Brilliant Blue R, Alkali Blue 6B,Tetrabromophenolphthalein, Victoria Blue, Lissamine Green B, Phloxine B.Erythrosin B, Rose Bengal, Basic Blue 3, Nile Blue, Methylene Blue,Methylene Green, Stains All, Disperse Blue 3, Alcian Blue 8GX, PrussianBlue, Tetraphenylbutadiene, and Dicinnamalactone can be used forintensification of the image.

Many diacetylenes, such as 155, 166, 156 and their cocrystallizedmixtures can be crystallized into inactive forms from their melt.Diacetylenes which do not undergo a phase change to an inactive phaseupon heating can be fixed upon heating if the coating also containsreagents which can chemically or physically (e.g., via hydrogen bonding)react with functionalities of diacetylene molecules and make themunpolymerizable. It is preferred that the binder has the ability toreact to make molten diacetylenes inactive. The most preferred method offixing the film is dry fixing.

Ionic and nonionic surface active agents can be used as emulsifiers.Pluronic®, Gafac® RS-710, sodium dodecyl sulfate, cetyltrimethylammonium chloride, ethoxylated para-octylphenol, 2-ethyl-hexyl alcoholethoxylate, lecithin, polyethylene glycol and PEG-dodecylether are someexamples of surfactants which can be used to make the emulsion. Use ofinorganic surfactant/emulsifiers, e.g., zinc oleate is preferred as theycan also act as convertor materials. Preferred concentration ofsurfactant in the mixture is 0.01 to 5%, most preferred is 0.1-1%.

A wide variety of solvents, from completely miscible, e.g., methanol toimmiscible, e.g., dichloromethane and ethylacetate, in water, can beused to make the emulsion. The use of different solvents is demonstratedin Examples 14, 17, 18, 19, 20, and 22. The preferred solvents aremethanol, MEK, ethylacetate and toluene. Preferred concentration can be5-80%, most preferred concentration range is 10-30%.

The emulsion can be prepared by processes, such as high speedhomogenization and ultrasonication. Vigorous agitation, e.g., high speed(100 rpm to 20,000 rpm) stirring is a preferred method of making theemulsion. In the case of a microemulsion, the mixture is usually clearand hence, may not require vigorous agitation.

The temperature of homogenization or emulsification will depend on themixture. The preferred temperature is above room temperature to up toabout 100° C. The most preferred temperature range is 40°-70° C.

An emulsion can be prepared by using techniques described in"Encyclopedia of Emulsion Technology, P. Becher (Ed.), Marcel Dekker,New York, 287 (1983); "Practical Emulsions", H. Bennett, J. C. BishopJr., and M. F. Wulfinghoff, Chemical Publishing Company, New York, 1968;and "Microemulsions: Structure and Dynamics", S. E. Frieberg and P.Bothorel, CRC Press, Boca Raton, Fla. Ernulsions are usually prepared byhomogenizing/emulsifying two immiscible liquids, e.g., a waterimmiscible solvent (e.g., toluene) with water using an emulsifyingagent, such as a surfactant. We have discovered several processes ofpreparing emulsions/dispersions of compositions. The processes areexemplified with radiation sensitive formulations, such as diacetylenes.

The methods of making emulsions of diacetylenes are preferred withoutone or more of the following basic components for making emulsion: (1)solvent for diacetylene and binder, (2) binder (3) emulsifying agent.These processes are described in Examples 14-21. The processes of makingnonaqueous emulsions, Example 18, and semi-aqueous emulsions, example19-21 are also preferred. Using one or more of the above methods, it ispossible to make an emulsion of most diacetylenes under a variety ofconditions, such as the use of a nonaqueous binder. The emulsions shouldbe cooled to a lower temperature for crystallization of diacetylenes. Inorder to prevent agglomeration of emulsion droplets, the emulsions aresolidified by pouring into a volatile liquid, such as liquid nitrogenand ammonia. The preferred methods of controlling crystal size are bycontrolling parameters, such as (1) nature and concentrations ofdiacetylene, solvents, binder, and emulsifier, (2) temperature anddegree of homogenization, (3) rate of quenching the emulsion, (4)temperature at which the emulsions are cooled, and (5) temperature ofcrystal growth.

The emulsions and processes are such that either at room temperature orat the temperature of coating, the radiation sensitive compositionscrystallize out and hence evaporation of the solvent used to dissolvethe radiation sensitive composition is not required. However, reducedamount of the solvents is desired in raising the temperature of dryingthe coating and to minimize the air pollution.

Only processes where crystals do not grow by cooling the emulsion atroom temperature is where the emulsion can be made with a solvent whichis very good solvent for the radiation sensitive composition and ishighly insoluble in water. For example, an emulsion made by emulsifyinga solution of a diacetylene in a solvent, such as toluene andethylacetate with water. When this process is used, the crystals grow onthe substrate after the emulsion is coated on the substrate. For allother processes, evaporation of solvent is not required for the crystalgrowth prior to coating. For those processes, the crystals grow once theemulsion is cooled to a lower temperature, e.g., below thecrystallization temperature.

The preferred temperature for cooling the emulsion is at roomtemperature or below. The preferred method of cooling the emulsion is byquenching the emulsion quickly to the desired temperature, for example,by (1) pouring the emulsion in a cooled tray, (2) by passing it througha cooling coil, and (3) by pouring in a volatile liquid, such as liquidnitrogen. If the emulsion is cooled quickly to a lower crystallizationtemperature, narrow distribution of the crystals is obtained, Thepreferred method of quenching is pouring the emulsion into a coldvolatile liquid, such as liquid nitrogen mainly because (1) it does notrequire aging of the emulsion, (2) freezing of the emulsion prevents theemulsion droplets from accumulation, (3) crystal size can be controlledfrom a fraction of a micron to several microns thick, (4) it can beeasily scaled up, (5) emulsions of a large number of diacetylenes can beformed in a variety of binders in both aqueous and nonaqueous systems,and (6) once the emulsion is solidified with liquid nitrogen, it can bethawed at any time.

The emulsions can be coated on a substrate using conventional orspecialized coating techniques including a Bird type film applicator(doctors blade or knife over roll technique), gravure bars and wirewound rods. The wire wound rods provide a more uniform coating in thelaboratory. A piece (e.g., 15×30 to 30×45 cm²) of polyester film isplaced on the platform of a draw down machine (Precision Draw DownMachine, Paul Gardener Company, Pompano Beach, Fla.). An emulsion ispoured in front of a wire wound rod (usually number 20 or 30). The rodis pulled at an even motion. The film is removed and the coating isallowed to dry at room temperature.

For best performance, the formulations and the processes for making thefilm should be optimized. The following formulations and processesrepresent optimized processes for making the film:

DIACETYLENES: The 9010 and 8515 cocrystallized diacetylene mixturesprovide the best compromise between reactivity, color, crystal growth,and thermal fixing ability. Films were made from both the formulationsusing a pilot plant coater. The 8515 film was characterized and used forthe field testing.

BINDER: PEl has very low toxicity and forms complexes with a largenumber of convertors for neutrons, electrons and X-ray radiation, PEl/BAprovided a transparent coating and good control properties over crystalsize. The concentration of PEl/BA is generally about 25% (total solid).

SOLVENT: MEK was used as a solvent for 9010 and 8515. MEK has lowtoxicity, forms better emulsion with PEl/BA solution, has highsolubility for diacetylenes, yields highly reactive phases of 9010 and8515, and reduces the thermal reactivity.

RATIO OF BINDER:DIACETYLENE: Mixtures of the binder and 9010/8515 havinga ratio of 5 to 0.3, particularly 4.3, provided a transparent film.

EMULSION PROCESS: A mixture of PEl/BA/DA/MEK forms a very fine emulsionat 60° C. at a high speed of homogenization within a few minutes. Theratio of PEl/BA/8515/MEK used in large scale preparations is given inExamples 21 and 22.

CRYSTAL GROWTH PROCESS: Quenching the emulsion with liquid nitrogenfreezes it and thawing the frozen emulsion at higher temperatures (e.g.,15° C.) provided control over the particle size of the crystals.Annealing the frozen emulsion between 15° and 20° C. provided crystalsof about 0.5-1.0 micron thick and 3-20 microns long.

METHODS OF COATING: In the laboratory wire wound rods were used while ona larger scale, reversed roll gravure methods for coating was used. Inthe laboratory, most of the coatings were allowed to dry at roomtemperature over a few hours period while on the larger scale thecoatings were dried between 35° and 50° C. in about five minutes.

SUBSTRATE: Polyester was chosen for its dimensional stability andclarity.

SUBSTRATUM: Commercially available Cronar® film which has a subcoat ofgelatin and another proprietary polymer were used.

SUPERCOAT: Gelatin was used as the supercoat because of its scratchresistant properties. The thickness of the supercoat was about 3microns.

THICKNESS: As a compromise between the reactivity and transparencycharacteristics, the thickness of the radiation sensitive coat(PEl/BA/8515) was about 15 microns.

FIXING 8515: One of the main reasons for the selection of 9010 and 8515is their ability to crystallize into an inactive phase from their melt.The film made from 8515 was fixed by heating the film above 80° C. Thecrystals of 8515 melt when the film is heated above 80° C. in an oven.The film was also be fixed by passing it through a heat laminator. Thediacetylene crystallizes into an inactive phase when the film is cooledto room temperature. The fixed film can be left under the ambient lightfor months with little or no effect of incident white light. In theabsence of the light, the film can be stored for years with very littledevelopment of additional color.

The thermally fixed film can provide sufficient archival image life.However, if required, the film can be further fixed by dipping in anontoxic polar organic solvent, such as ethanol or tetrahydrofuran. Theunreacted monomer molecules get extracted with tetrahydrofuran bydipping the film in the solvent for about five minutes at roomtemperature. The resultant fixed film is transparent and totallyunaffected by UV light and temperature. The film can also be fixed bydipping it in ethanol for about five minutes at room temperature,However, this procedure makes the film opaque. The ethanol fixed filmwas made transparent by dipping in water for less than a minute at roomtemperature. Water dissolves/swells PEl/BA and upon drying the coatingbecomes transparent.

It is not necessary to heat a film containing a diacetylene to itsmelting point if it undergoes a phase change from active to inactivebelow its melting point.

In order to select the screen for 8515 film, thin foils of variousthicknesses (0.01 mm to 1.6 mm) of some metals ,were tested as the topand bottom screens for megavolt radiations. As a top screen, most of themetals attenuate the megavolt beam and there is no significantamplification of the image. However, most of the heavy metals amplifiedthe image when used as the bottom screen. Pieces (about 2×2 cm²) ofmetal foils were mounted on a 0.2 mm thick Mylar®. A piece of thediacetylene film was placed on the metal foils. The films wereirradiated with 100 and 200 rads of 10 MeV X-ray and 12 MeV electrons.The optical density of the exposed areas were measured. The results aresummarized in Table 4. The optimum effect was observed with about a onemillimeter thick lead screen. A one millimeter thick lead screenamplifies the image by about two times. The amplification is lower forelectrons.

                  TABLE 4                                                         ______________________________________                                        Increase in Optical Density of the 8515 Film by Screens of                    Different Metals of Varied Thicknesses.                                       The Film was Irradiated with 200 Rads of 10 MeV                               X-ray and 12 MeV Electrons.                                                                           Optical Density                                       Metal     Thickness (mm)                                                                              X-ray   Electron                                      ______________________________________                                        None      --            0.12    0.11                                          Tin       0.1           0.15    0.12                                          Silver    0.127         0.16    0.12                                          Gold      0.01          0.15    0.13                                          Zinc      0.25          0.15    0.12                                          Ag:Pd (1:3)                                                                             0.127         0.16    0.13                                          Lead      1.6           0.19    0.15                                                    1.0           0.19    0.16                                                    0.5           0.19    0.15                                                    0.25          0.18    0.14                                          Copper    1.27          0.15    0.13                                                    1.0           0.15    0.13                                                    0.635         0.15    0.12                                                    0.25          0.15    0.12                                                    0.127         0.14    0.12                                          Brass     0.5           0.16    0.12                                                    0.25          0.16    0.12                                                    0.127         0.15    0.11                                                    0.025         0.14    0.11                                          ______________________________________                                    

A 30×45 cm² cassette was made by using a 1.6 mm thick lead foil. Themetal foil was bonded to a 5 mm thick section of Plexiglass®. The samesized piece of Plexiglass® was covered with 0.2 mm Mylar® film (toprotect the 8515 film from UV light) and was used as the top transparentlid of the cassette. The film was sandwiched between the lead foil andthe top lid, and exposed in separate experiments to 10, 25, 75, 100, and200 rads 10 MeV X-ray radiation. The film was exposed to the samedosages in a commercially available Kodak cassette. After theirradiation, visible spectra of the samples were recorded. Theabsorption at 584 nm for the films exposed in this cassette wasessentially the same as that exposed with the Kodak cassette. Theresults indicate that a commercially available cassette for measuringX-ray radiation can be used.

The pieces of the 8515 film were irradiated with different dosages, from5 to 1,000 rads of 10 MeV X-ray radiation. A piece of 2.5 centimeterthick Lucite® was used as the build-up. The source to surface distancewas 100 cm and the field size was varied from 10×10 cm² to 20×20 cm².

A typical set of visible spectra of the films irradiated with differentdosages of X-ray radiation is shown in FIG. 3. The dose is indicated oneach spectrum. The film develops a noticeable faint pink color at about10 rads. The peak at 584 nm becomes two peaks at higher radiation doses.

A typical set of visible spectra of the fixed film prepared by heatingthe irradiated films in FIG. 3 is shown in FIG. 4. The film was fixed byheating it at 80° C. for 5 minutes in an oven. The appearance of thepeak at 620 nm provides a purple color to the film at higher radiationdosages. The peak at 620 nm becomes dominant as the radiation doseincreases and shifts towards higher wavelengths. Because of this shift,the fixed film develops a blue black color at higher radiation dosages.

The G value (number of monomer molecules polymerized per 100 eV ofenergy) was determined by irradiating 9010 at different dosages of fastneutrons, X-rays, and electrons followed by determination of thefraction of monomer polymerized by the extraction method. On order todetermine G.sub.(-m,O), the plots of G-value versus dose wereextrapolated back to zero dose. The G.sub.(-m,O) values are reported inTable 5. For a given dose, the G value is lowest for neutrons becauseneutrons do not interact with orbital electrons. Hence, neutrons areunable to initiate polymerization. However, the interaction of neutronswith hydrogen nuclei can produce protons which can initiatepolymerization. Electrons and X-rays, including the secondaryradiations, can interact with orbital electrons to initiatepolymerization. The highest G-value for X-ray radiation indicates thatmore secondary, lower energy radiations are produced by X-rays than byelectrons.

                  TABLE 5                                                         ______________________________________                                        G.sub.(-m, 0) Values of 9010 for Neutrons, Electrons and X-rays.              Radiation   Neutrons   Electrons X-ray                                        ______________________________________                                        Energy (MeV)                                                                              20         12        10                                           G.sub.(-m, 0)                                                                             55 × 103                                                                           180 × 103                                                                         320 × 103                              ______________________________________                                    

The G-value for the Fricke dosimeter is low, ca., 15.5. Hence, theradiation dose in kilorads is required for calibration of sources. TheG-.sub.(-m,O) value for 9010 is 320,000±50,000 for X-rays. That is abouttwo thousand times higher than Fricke dosimeter. Because of thesignificantly high G-value for diacetylenes, significantly lowerradiation doses will be required. The results also indicate that becauseof the high G-value, diacetylenes offer a unique opportunity ofdeveloping an absolute dosimeter for the calibration of sources andfilms for quality control and verification made from the same tissuespecimen.

A simple, fast, and accurate primary dosimeter can be developed using aproper diacetylene. In order to prevent any polymerization duringstorage, an inactive phase of a diacetylene, such as that of 144 can beselected. Before the diacetylene is irradiated, it should becrystallized into an active phase from a suitable solvent and dried.However, in order to avoid polymerization during drying, one can selecta solvent which dissolves the diacetylene at a high temperature andprecipitates/crystallizes it at room temperature. Solvents, such as amixture of ethanol and water are desirable. Instead of drying thecrystals, the wet crystals can be irradiated at different radiationdosages up to 1,000 rads. The polymer conversion (fraction ofpolymerized monomer) can be determined by heating the irradiated mixtureat a high temperature to dissolve/extract unpolymerized monomer and thenfiltering out the polydiacetylene molecules. A simple Soxhlet extractorcan be used for extraction of the unreacted monomer. G-values can thenbe determined by using the following-equation: ##EQU1## Where,G.sub.(-m) is the G-value for polymerization of the monomer, N isAvogadro is number, C is fractional polymer conversion, M is molecularweight of monomer, and D is radiation dose in rad.

The process of calibration of the sources can be simplified by supplyingsmall vials containing an inactive diacetylene dispersed in propersolvent(s). The user can heat the vial to dissolve the diacetylene andthen cool to room temperature for crystallization into the active phase.After irradiation, the vial is heated again to dissolve both monomer andpolymer, and the color intensity is determined. From the calibrationplots one can quickly determine the dose.

This invention further provides a utility of the film, diacetylenes andother formulations, such as a human skin lotion made from diacetylenes.The film can be imaged with, and information can be recorded withradiation having energy from short wavelength (300 nm) UV light to X-raytherapy radiation (about 40 MeV). It can also be used for monitoringlower energy nuclear particles, such as thermal neutrons (e.g., 0.025eV). The film can also be used for monitoring radiation dose. The filmcan also be used for a variety of applications, such as a dosimeter forradiation, monitoring processes, such as radiation therapy, curing ofcoating and cross-linking of plastics, for recording images andinformation, and as microfilm and radiography film. In each of the aboveutility applications, there are a number of other applications, forexample, for radiation therapy, the film can be used for verification,imaging, field size coincidence, as a transmission check, measuringportal radiation and beam data acquisition (depth dose, field flatness,beam symmetry and dosimetry), and mapping/calibration of brachytherapy.

For certain applications, such as the precise beam localization inradiation therapy, a solution/dispersion of diacetylene in form of anemulsion, solution, skin lotion or cream can be used. For example, thelotion can be applied on the skin of the patient at the entrance andexit points of the beam. Upon irradiation, the exact location of theentrance and exit of the beam can be determined. Skin lotions/creams canbe aqueous or alcoholic aqueous. The lotion can be emulsified ornon-emulsified. The lotion may contain several additives. The lotion canbe prepared as a fine dispersion or solution of diacetylenes in water oralcohol along with other ingredients, such as binders (e.g. starch, gumsand cellulose derivatives), emulsifying agents (e.g., lecithin, estersof fatty acids) and other additives, such as mineral oil, cetyl alcohol,triethanolamine, and the like. There are several alternatives to thelotion. For example, a solution of diacetylenes containing all otherrequired additives can be spray coated onto the body at the desiredradiation sites.

Radiation sources are calibrated with a tissue equivalent ionizationchamber immersed in a tissue equivalent liquid and the dosedistribution/profile of the radiation field is prepared. The detectionmaterials of absolute/primary dosimeters, such as calorimeters,ionization chambers, and Fricke (ferrous sulfate), and the secondarydosimeters, such as silicon diode and thermoluminescence materials ofdosimeters (used for calibration of sources), and that of silver halidefilms (used for quality control and verification) are not tissueequivalent. Thus, it is desirable to have a primary dosimeter used forcalibration of radiation sources and the films used for the qualitycontrol and assurance should be made from the same tissue equivalentmaterial. The present device can be used as a primary/absolute dosimeterfor calibration of sources and films for quality control andverification of the therapy made from the same class of materials.

As a dosimeter, the film offers the following major characteristics,benefits, and advantages over the other dosimeter devices availablecommercially: It is a small, simple, low cost, and light weight device.Any sized dosimeter film can be prepared which acts as a passivedosimeter and does not require electronic equipment and can be used as adosimeter over a very wide radiation dose range, from 5 to 500 rads.Higher radiation doses also can be determined. As diacetylenes areorganic compounds having a density of about 1.1±0.1 gram/cc, the filmwill be tissue equivalent. The diacetylenic based formulations, such asa lotion or cream, and devices, such as films and labels, can be usedfor monitoring UV exposure, e.g., by sunbathers. By selectingdiacetylenes and their mixtures having proper radiation reactivity, onecan match the UV exposure for sun bathers. The diacetylene basedformulations and devices will undergo either blue or red color change.The UV exposure can be estimated from a reference color chart.

Diacetylenes, such as 166 and their cocrystallized mixtures, which whenexposed to UV light, turn red and when heated at about 80° C. turnblue/black and become fixed, and can be used for making a high speedprinting paper. A paper coated with such a diacetylene composition canbe printed using a mask at extremely high speed. Printing can be donewith a UV lamp using a negative/mask or using a UV laser. When the paperis heated, e.g., by passing between heated rollers, it will turn red,blue or black color. The printing papers can be prepared by coating themwith an ink, emulsion or solution of the diacetylene composition.Desired colors can be obtained by mixing proper diacetylenes in properproportions.

Medical supplies are sterilized with gamma-ray, X-ray and electrons. Theradiation dose required for the sterilization varies from a few hundredkilorads to a few megarads. (Mrads). The shelf life of whole blood andthat of a wide variety of foods is extended by irradiating with lowdosage (1-100 kilorads) gamma rays and electrons. Many coatings arecured by UV light and UV curable inks are widely used to avoid airpollution. The radiation dose for all these applications can bemonitored using a diacetylene, such as 166. In contrast to otherdiacetylenes, the radiation dosage indicator made from a diacetylene,such as 166, can be fixed by heating.

In order to see the printing of electrical circuits, photoresists of aprinted circuit board and/or computer chip can either containinherently, or can be coated with a photosensitive dye. When thephotoresist is exposed to UV light, the developed electrical circuit canbe seen. As diacetylenes polymerize to colored polymer upon irradiation,a photoresist or a coating of diacetylene will produce a color image ofthe circuit.

An item, e.g., a paper or an article of commerce, printed or coated,wholly or partially, with a diacetylenic ink or paint, can be used forits identification. The properties of diacetylenes, such as developmentof color upon UV exposure, reversible and/or irreversible color changeand/or fluorescence change upon heating, can be used to identify thecoated item.

EXAMPLES

The following Examples are illustrative of carrying out the claimedinvention but should not be construed as being limitations on the scopeand spirit of this invention.

Example 1

Synthesis of 166, 2,4-Hexadiyn-1,6-bis(n-Hexylurethane),R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₅ CH₃ :

Into a 500 ml round-bottom flask equipped with a magnetic stirrer, a 125ml addition funnel and a drying tube were placed a magnetic stirringbar, 19.6 gram of 2.4-hexadiyn-1,6-diol and 300 ml of dichloromethane.The mixture was stirred at ambient temperature for ten minutes todissolve the diol. To this solution were added 0.178 gram of dibutyltinbis(2-ethylhexanoate) and 1.8 ml of triethylamine as catalysts. Themixture was stirred for another ten minutes and then a solution of 50.0gram of n-hexyl isocyanate (98%, 0.385 mole) in 50 ml dichloromethanewas added dropwise at 25° C. within half an hour. At the end of theaddition, the mixture was stirred at 25° C. for two hours. The reactionwas allowed to proceed for a few hours at RT (room temperature) and then10 ml of methanol was added. The mixture was heated to about 50° C. andstirred for one hour, cooled to ambient temperature and filtered. Thesolvents were removed under vacuum to give 67.9 gram of solid. Onerecrystallization of the crude material yielded 49.6 gram of the titlecompound, 166. A second recrystallization from methanol gave 166 with am.p. 84.5°-85.5° C.

Example 2

Synthesis of 9010 (A 90:10 Weight Percent mixture of 166:156) 166:R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₅ CH₃. 156:R'--C.tbd.C--C.tbd.C--R", where R'=--CH₂ OCONH(CH₂)₄ CH₃ and R"=--CH₂OCONH(CH₂)₅ CH₃

Into a five liter round bottom flask equipped with a stirrer were added494 gram (4.5 mole) of 2,4-hexadiyn-1,6-diol and 1700 ml of anhydrousTHF. The mixture was stirred in warm water bath (35° C.) to dissolve thediol. To the solution were added 4.5 gram of dibutyltin bis(2-ethylhexanoate) and 45 ml of triethylamine. The solution was cooled to about8° C. Then 53.9 gram (0.47 mole) of n-amyl isocyanate was added dropwiseover 15 minutes. Temperature rose from 12° C. to 15° C. The mixture wasstirred for additional 30 minutes at 15° C. 1196 gram of n-hexylisocyanate (9.4 mole) was added dropwise over 75 minutes. During theaddition the temperature was maintained between 15° and 25° C. with anice-water bath. After half an hour the temperature of the reaction wasraised to 50° C. The reaction was allowed to proceed for about half anhour and then 100 ml of methanol was added. THF was then removed undervacuum and the crude product was dissolved in hot isopropyl ether andfiltered. The filtrate was cooled overnight at RT for crystallization of9010. The crystals were filtered and air-dried to give 1490 gram (91.5%yield) of the title 9010 mixture, a solid, m.p. 82° C. to 84° C. Thesolid was recrystallized from five liters of isopropanol at -30° C. toyield 1370 gram of a solid, m.p. 84.5° C-85° C.

Example 3

Synthesis of 8515 (A 85:15 Weight Percent mixture of 166:156). 166:R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₅ CH₃. 156:R'--C.tbd.C--C.tbd.C--R", where R'=--CH₂ OCONH(CH₂)₄ CH₃ and R"=--CH₂OCONH(CH₂)₅ CH₃

Into a 5 liter round bottom flask equipped with a magnetic stirrer,thermometer, 1 liter addition funnel and a drying tube were placed 390gram (3.54 mole) of 2,4-hexadiyn-1,6-diol and 7.1 gram of dibutyltinbis(2-ethylhexanoate). THF (1800 ml) was added and the mixture wasstirred at RT to dissolve the diol and the tin catalyst. Triethylamine(35 ml) was then added with stirring at -10° C. n-Pentyl isocyanate(69.7g, 99%, 0.61 mole) was added over 10 minutes stirring. The mixturewas cooled to 12° C. with an ice-water bath and 980 gram (99%, 7.63mole) of n-hexyl isocyanate was added in a small stream over 55 minuteswhile the reaction temperature was maintained at 12° to 16° C. Theresulting mixture was stirred at about 15° C. for 1 hour. Thetemperature of the reaction was then raised to about 50° C. The mixturewas stirred for 30 minutes, cooled to 40° C. and methanol (100 ml) wasadded to destroy excess isocyanate which caused the temperature to riseto 50° C. The contents were cooled to 35° C. and then stirred for onehour. About 1500 ml of the solvent was removed with a rotary evaporatorunder vacuum and the residue was added to 4500 ml of isopropyl ether.The mixture was reheated to give a complete solution, cooled to RT andthen placed in the refrigerator overnight for crystallization. Theresulting crystals were filtered, and washed with 1000 ml of chilledisopropyl ether and then dried (crude weight 1240 g).

The solid was dissolved in 4.5 liter of hot isopropanol, filtered andthe filtrate was cooled in a freezer (-30° C). The resulting crystalswere filtered, washed with 1000 ml of cold isopropanol and dried to give1020 gram. Another crystallization from isopropanol gave 908 gram of thetitle mixture, 8515.

Example 4

Synthesis of 9010-16PA (A 90:10 Weight Percent mixture of 166:16PA).166: R--C.tbd.C--C.tbd.C--R, where R=--CH₂ OCONH(CH₂)₅ CH₃. 16PA:R'--C.tbd.C--C.tbd.C--R", where R'=--CH₂ OCOCH₂ C₆ H₅ and R"=--CH₂OCONH(CH₂)₅ CH₃

Into a 500 ml round bottomed flask was charged 27.5 gram of2,4-hexadiyn-1,6-diol and 250 ml of THF. After stirring at ambienttemperature, 19.8 gram of triethylamine was added. Then, phenyl acetylchloride (7.9 gram) was added dropwise over about 5 minutes.Precipitation occurred during this addition, apparently due to theformation of triethylamine hydrochloride. Stirring at near ambienttemperature was continued for several minutes. Then 64.6 gram of n-hexylisocyanate was added dropwise over 15 minutes. The temperature of thereaction was maintained to about 20° C. with cold water. The resultantmixture was stirred for 10 more minutes, then heated up to 45° C.-50° C.for 20 minutes. Methanol (10 ml) was then added at 50° C. and allowed tocool to ambient temperature. The mixture was filtered and the residuewashed with 10 ml methanol. The filtrate and washings were evaporatedwith a rotary evaporator under vacuum. The residual (viscous liquid) wasadded to 500 ml of isopropyl ether and the mixture heated to dissolve,cooled, and the resulting solid formed was refiltered (the solid was theamine hydrochloride). The filtrate was placed in a refrigerator forcrystallization. The solid was filtered after a day to yield theabove-titled mixture, 9010-16PA. The solid was highly reactive to UVlight. A film was made using the procedure similar to that described inExample 21. The film partially polymerized to a red color when exposedto UV and x-rays. The radiation reactivity is similar to that 166. Thefilm turned blue/purple when heated at 85° C. The heated film is highlyinactive to UV light.

Example 5

Co-crystallization of Tricosa-10,12-diynoic acid (TC) andPentacosa-10,12-diynoic acid (PC): Tricosa-10,12-diynoic acid[HOOC--(CH₂)₈ --C.tbd.C--C.tbd.C--(CH₂)₁₀ H], andPentacosa-10,12-diynoic acid [HOOC--(CH₂)₈ --C.tbd.C--C.tbd.C--(CH₂)₁₂H] were obtained from Farchan Laboratories, Inc. Following mixtures wereprepared in test tubes, melted and thoroughly mixed. Each mixture wasdissolved in 2 ml chloroform coated on filter paper strips by dipcoating and exposed to short wavelength (254 nm) UV light. Table 6summarizes the results:

                  TABLE 6                                                         ______________________________________                                        Radiation Reactivity of PC, TC and their Cocrystallized Mixtures.             Name of Wt. of  Wt of   TC   PC    m.p.  Ultra-violet                         Mixture TC (g)  PC (g)  %    %     (°C.)                                                                        Reactivity                           ______________________________________                                        PC      0.0     0.5      0   100     62.3                                                                              Poor                                 TP14    0.1     0.4     20   80    55-58 Fast                                 TP23    0.2     0.3     40   60    53    Fast                                 TP32    0.3     0.2     60   40    50-52 Fast                                 TP41    0.4     0.1     80   20    53    Very Fast                            TC      0.5     0.0     100   0    54-56 Poor                                 ______________________________________                                    

Five percent solutions of TC, PC and TP41 were prepared in acetone. Thediacetylenes were coated on filter papers by dip-coating and exposed toa short wavelength UV light (from Model UVG-11,254 nm lamp made UVPInc., San Gabriel, Calif.) for a few seconds. Visible spectra of TC, PCand TP41 were recorded. The absorbance peak at 640 nm of TP41 was about20 times higher than PC and about 5 times higher than TC. Film of TP41was also similarly more reactive than PC and PC. When the films of TC,PC and TP41 are exposed to UV light, they develop blue color. The bluecolor intensifies with the dose. When the partially polymerized filmsare heated above the melting points of the diacetylenes, they undergo anirreversible blue-to-red color change. The films further undergo areversible red-to-yellow color change when heated further near and abovethe melting points of the polydiacetylenes.

Example 6

Preparation of PEl/BA complex: To 250 grams of a warm solution of 30%PEl (Polyethyleneimine) solution in water (75.1 gram, 1.75 mole of PEl)was added 108 grams (1.75 mole)of boric acid under vigorous stirring.The boric acid complexed rapidly and completely to form a clearsolution. In the absence of PEl, the solubility of boric acid is onlyabout 5%. The coating of this solution provided a glass like highlytransparent coating.

Example 7

Preparation of other complexes of PEl: Different organic and inorganiccompounds, which can be used as convertors, were added to differentconcentrations of PEl solution. The mixtures were stirred and coatedonto polyester film. Properties of the resulting films are summarized inTable 3 with some of the representative compounds.

Example 8

Plasticization of PEl/BA: To 10 ml of 15-30% solutions of PEl/BA wereadded different low molecular weight and polymeric plasticizers, such asdioctylphthalate, polyethylene glycol, polyethylene glycol distearate,polyethylene oxide, polyvinyl alcohol, gelatin, polyacrylamide,polyethyleneimine, polyvinylpyrrolidone, ammonium oleate, sodium oleate,dodecyl sulfate heptanoic acid, hexanoic acid, palmitic acid, oleic acidand propionic acid. The mixtures were thoroughly mixed and coated ontoMylar® and Cronar® films using a #20 wire wound rod. The coatings wereallowed to dry either at RT or in an oven between 50° C. and 110° C. forhalf an hour. The films were then bent/creased sharply at 180° and thenbent back to make the film flat by applying pressure along the creasedline. The degree of plasticization was determined from the crazing ofthe coating. A good plasticizer should either prevent or minimize thecrazing. Maximum prevention of the crazing was obtained with propionicand heptanoic acid, prevented the crazing. The following formulationprovided a coating which did not crack or craze: 143 gram of 30% PEl, 43gram of boric acid and 22 gram of propionic acid.

Example 9

Monitoring Alpha Particles: A 8515 film prepared according to Examples21 and 22 was exposed to alpha particles from a commercially availableantistatic source of 50 micro Curie polonium-210 for five minutes.Polonium-210 emits alpha particles of 4.5 MeV. The image of the sourcewas obtained in red color. The results indicates that the film can beused for monitoring alpha particle therapy treatment. When boron-10 isirradiated with neutrons, it emits alpha particles.

Example 10

Substratum: To nine parts of 10% polyvinylacetate in ethanol:water (4:1)was added 1 part of 10% low molecular weight polyacrylic acid inethanol. The molecular weight of the polyacrylic acid was 2,000. Themixture was coated onto a polyester (e.g., Mylar®) film and dried eitherat room temperature or in an oven at 80° C. The adhesion of thesubstratum coating with polyester and PEl/BA was tested by thecross-hatch test (ASTM method #D-3359). Under this method, the coatingis cut crosswise with a very sharp, narrow blade knife with a distanceof 2 mm between the cuts. One end of an adhesive tape was firmly appliedon the cross-hatch. The tape was pulled from the other end. The tape didnot lift the substratum.

Example 11

Complexes (solid solution) of inorganic compounds with gelatin: In orderto use inorganic complexes or solid solutions of gelatin as binders, forradiation sensitive compounds, in the substratum, radiation sensitivecoat, and top coat, to amplify images upon irradiation with high energyradiations, various amounts of different inorganic salts were added to20 ml of 10% gelatin solution in water at about 45° C. The mixtures werecoated onto a polyester film. The clarity and tackiness of the coatingswere noted. The results are summarized below in Table 7 for someselected salts:

                  TABLE 7                                                         ______________________________________                                        Complexes/Solid Solutions of Gelatin with some Inorganic                      Compounds.                                                                    Salts    Amount (g) Results                                                   ______________________________________                                        Boric acid                                                                             0.5        Particles                                                 Bal.sub.2                                                                              0.3        Clear, nontacky                                                    2.0        Light yellow, transparent, nontacky                                4.0        Light yellow, transparent, nontacky                       Nal      0.8        Clear, nontacky                                                    1.8        Light yellow, slightly tacky                              Snl.sub.4                                                                              0.3        Light yellow, nontacky                                             0.7        Light yellow, particles, nontacky                         SnCl.sub.4                                                                             1.8        Clear, nontacky                                                    1.8        Clear, nontacky                                           ZnCl.sub.2                                                                             1.3        Clear, nontacky                                                    4.2        Clear, slightly tacky                                     ZnBr.sub.2                                                                             1.0        Clear, nontacky                                                    3.5        Clear, slightly tacky                                     Znl.sub.2                                                                              0.5        Clear, nontacky                                                    0.9        Slightly turbid                                           ZnSO.sub.4                                                                             0.5        Clear, nontacky                                                    1.1        translucent                                               ______________________________________                                    

Example 12

Complexes (solid solutions) of inorganic compounds with polyacrylicacid: To 5 ml of 17.5% solutions of polyacrylic acid (mol. wt. 90,000)were added 0.3 and 0.6 gram of potassium iodide and 0.4 gram ofmagnesium acetate. The solutions were coated onto a polyester film. Thecoating containing 0.3 gram of potassium iodide was clear while thatcontaining 0.6 gram became translucent. The coating containing 0.4 gramof magnesium acetate resulted in a transparent coating.

Example 13

Mixtures of fine powders of inorganic materials: About 3 ml of differentaqueous polymer solutions were placed in a test tube and 1.5 to 2 mlportions of 40% colloidal silica (SiO₂, pH-9) were added and mixed. Themixtures were coated on a polyester film. The results are summarizedbelow in Table 8.

                  TABLE 8                                                         ______________________________________                                        Dispersion Of SiO.sub.2 in some Binders.                                                        Colloidal                                                   Polymer Conc.     SiO.sub.2                                                                              Property of the coating                            ______________________________________                                        None    --        --       Clear but brittle coating                          PEO     3 ml 5%   1.5 ml   Clear transparent coating                          PEI     3 ml 30%  2.0 ml   Thick gel, not coated                              PEI/BA  3 ml 15%  1.5 ml   White precipitate                                  PVP     3 ml 10%  1.5 ml   Thick gel, PVP precipitates.                       PVP     15 ml 0.7%                                                                              0.7 ml   Clear coating                                      PAA     3 ml 25%  2.0 ml   White precipitate                                  ______________________________________                                    

Example 14

Formation of emulsion without any binder: Into a jacketed blendercontainer were added 40 gram of water and two drops of GAF-710 and mixedat low speed. To the mixture was added 12 ml of a 100% (6 gram in 6 ml)solution of 9010 in MEK and homogenized for two minutes at 60° C. Thewhite emulsion formed was poured into (1) liquid nitrogen and (2) into atest tube at RT. The parts of the sample frozen at liquid nitrogen werebrought to RT, 8° C., and -20° C. and maintained for a day. The lowtemperature samples were then brought to room temperature.

The emulsion which was quenched to RT in the test tube was essentiallyinactive to UV radiation but became active within an hour. The samplewhich was quenched to liquid nitrogen and brought to RT became UV activealmost immediately. The samples stored at 8° and -20° C. were alsoactive. The sample quenched to RT had flat platelet type crystals whilethose quenched into liquid nitrogen had globule type crystals.

Two grams of the above emulsions were mixed with 2 gram of aqueoussolutions of (1) 30% PEl/BA and (2) 10% polyvinylpyrrolidone, mixed andcoated onto Mylar® film using a #30 wire wound rod. Both coatings weretransparent and UV active.

Two grams of the above emulsion was mixed with two grams of vinylacetatelatex (obtained from Monomer-Polymer & Dajac Laboratories, Inc.,Trevose, Pa.). and coated onto polyester film. The coating was UVactive.

Part of the above emulsion was freeze dried under vacuum. The driedcrystals were dispersed in a 20% solution of poly(iso-butylmethacrylate)in cyclohexane at room temperature and coated onto a plastic film. Thecoating was substantially transparent and UV reactive.

Example 15

Totally aqueous emulsions without binder: Into a jacketed blendercontainer was weighed 75 gram of water, 4 drops of Gafac-710 and 7.5gram of 9010. The temperature of the mixture was raised to about 95° C.by circulating hot water while homogenizing at high speed. The mixturewas homogenized for two minutes and then half of the emulsion was pouredinto liquid nitrogen while the other half was poured in to a petri-discat room temperature. Both the samples were allowed to come to roomtemperature.

5 gram of the emulsions were mixed with 30% PEl/BA solution and coatedonto polyester film. The coatings were not reactive to UV light because9010 crystallizes into an inactive phase from its melt. When 4BCMU wasused instead of 9010, the coating became UV active because 4BCMUcrystallizes into an UV active phase from its melt.

Example 16

Emulsion without using any solvent: 50 gram of polyethylene glycol,molecular weight, 14,000, was added into a jacketed container of ablender. Hot water (95° C.) was circulated to melt polyethylene glycol.5 gram of 9010 was added which dissolved in the molten polyethyleneglycol. The mixture was homogenized for two minutes at high speed andpoured into liquid nitrogen. The solid was allowed to come to roomtemperature. 5 gram of the solid emulsion was added into 10 ml of waterto dissolve polyethylene glycol and the dispersion was coated onto apolyester film. The resulting coating was translucent and UV reactive.

Example 17

Mixture of an emulsion and a latex: A 20 ml 15% (w/v) solution of 9010in toluene was emulsified with 10 ml of water in the presence of 0.2 mlof an emulsifier (e.g., Gafac RS-710) using a high speedblender/homogenizer for five minutes. The temperature was maintainedbelow 30° C. by circulating cold water. A milky white emulsion wasobtained. The emulsion was stable for months at RT without causingprecipitation of 9010 or a phase separation. The emulsion was not activeto UV light. The emulsion was then mixed with 20 ml of a vinyl acetatelatex (obtained from Monomer-Polymer & Dajac Laboratories, Inc.,Trevose, Pa.). The vinyl acetate (PVA) latex contained 50% PVA. Themixture of the latex and the emulsion was then coated onto Mylar® at 30and 90 microns wet thicknesses and dried at ambient temperature. Thecoating was transparent and UV reactive.

The emulsion of 9010 was also mixed with several other polymer latexes,such as those of vinyl chloride, ethylene/vinylacetate, vinylchloride/methyl acrylate, ethylene, 2-vinylpyridine,vinylpyrrolidone/styrene and styrene. The mixtures were then coated on apolyester film.

Example 18

Nonaqueous emulsions: Into a jacketed blender container was weighed 50gram of 10% (w/v) poly(isobutyl methacrylate) in cyclohexane. Stirringat a low speed, 2.5 gram of 9010 was added. The temperature of themixture was raised to about 55° C. to dissolve 9010 by circulating hotwater. While homogenizing at high speed, the temperature of the mixturewas lowered to 10° C. by circulating cold water. After 5 minutes, themixture was transferred into a beaker. The solution was coated ontoMylar after half an hour. The coating had fine long needle type crystalsof 9010 and was UV reactive.

The above experiment was repeated by adding solution of 9010 in acetone(2.5 gram of 9010 dissolved in 1 ml of acetone) in 50 gram of 10% (w/v)poly(isobutyl methacrylate) in cyclohexane. This coating also had longneedle type crystals and was more UV reactive than the above coating.

Example 19

Semi-aqueous System: Into a jacketed blender container was weighed 50gram of 30% (w/v) poly(vinylacetate) solution in 8:2 ethanol:water.While stirring at a low speed, 6 gram of 9010 was added. The temperatureof the mixture was raised to about 55° C. to dissolve 9010 bycirculating hot water. While homogenizing at high speed, the temperatureof the mixture was lowered to 15° C. by circulating cold water. After 5minutes, the mixture was transferred into a beaker. The solution wascoated onto polyester film after half an hour. The coating had fine longneedle type crystals of 9010 and was UV reactive. The mixture pouredinto liquid nitrogen had smaller needles.

Example 20

Formation of emulsion using a solvent which is highly soluble in water:To 40 grams of a 22.5% PEl/BA solution in a jacketed container of a highspeed homogenizer was added 0.1 ml (about 6-8 drops) of the GAF-710 asan emulsifying agent. The mixture was homogenized for about a minutewhile circulating cold water. To the homogenized solution was added 12ml of a 15% solution of 166 in methanol within about 5-10 seconds andthe mixture was stirred at high speed for 3-5 minutes. The temperatureof mixture was maintained below 30° C. The resultant emulsion was pouredinto a beaker and allowed to age at 25° C. for different periods of timeand then coated onto polyester film. The freshly coated emulsion wasalmost inactive. The UV reactivity increased upon aging for the firstfew days and achieved maximum reactivity after about 3 days. Examinationof crystals of the coating under an optical microscope indicates thatonly a small fraction of the crystals appeared to form during aging,while most of them became activated upon aging. The crystals were veryfine needles and the coating was transparent.

Example 21

Preparation of An Emulsion of 8515 for Large Scale Coating: The stocksolutions for making the emulsion were prepared as follows:

SOLUTION OF PEl/BA/OLEIC ACID: A 1:1 molar complex of PEl/BA(polyethyleneimine/boric acid) was prepared by dissolving 1948 gram ofboric acid in 4622 gram of a 30% (w/w) solution of PEl (AcetoCorporation, Lake Success, N.Y.). The complex was diluted with 1540 mlof water. To this solution was added 81 gram of oleic acid dropwisewhile stirring vigorously. This solution was further diluted with 1365ml of water.

SOLUTION OF 8515: 666 gram of 8515 was dissolved in 487 gram ofmethylethylketone at 70° C. and a small quantity of polymer was removedby filtration.

PREPARATION OF THE EMULSION: Into a four liter stainless beaker wasadded 1050 gram of the above stock solution of PEl/BA/Oleic and heatedto 60° C. To the solution was added 385 gram of the 8515 solution andhomogenized with a high speed mechanical stirrer for five minutes.Evaporation of the solvents was minimized by covering the container witha plastic film. A creamy emulsion was obtained. The emulsion was pouredinto about five liters of liquid nitrogen while stirring with amechanical stirrer. The mechanical stirrer converted the solidifiedemulsion into a powder. Using the above procedure, two more batches offrozen emulsion were prepared. All three batches were mixed.

The solid emulsion was spread into nine aluminum trays (60×30×3 cm³)trays and placed in a water bath at 20° C. The solid emulsion thawedwithin a few minutes. Some liquid oozed on the surface. After about tenminutes, oozed liquid (which was mainly water) was decanted off. Theemulsion was left in the trays for about half an hour and then stored atroom temperature under a hood. Only for this pilot plant batch, most ofthe solvents, especially MEK were allowed to evaporate for about fivehours and then transferred into a plastic jar and diluted with water toobtained 800 cP viscosity.

The emulsion was coated on Mylar® using #30 a wire wound rod and wasallowed to dry at room temperature. The coating was transparent andhighly reactive to UV light.

Example 22

Making of the film on a large scale: The emulsion prepared according tothe above Example 21 was coated onto a 100 micron thick, 30 cm widepiece of Cronar® using the reverse roll gravure technique using a pilotplant coater. The emulsion of 8515 was pumped into the boat in which thegravure bar rotated in the opposite direction of the film. A doctor'sblade removed excess emulsion from the bar. The polyester film waslowered to contact the gravure bar. The emulsion became coated on thefilm and slowly moved into the oven where it was dried and wound ontake-up roll. The film was then coated on the back side under theidentical conditions. Using the gelatin solution, PEl/BA/8515 coatingwas top coated with gelatin first on one side and then on the other. Thegelatin concentration was 10% and the gravure rod used was a #110. Otherdrying and coating conditions for the gelatin top coatings wereidentical to that of the diacetylene coat. Because of the shorter dryingpath, higher oven temperatures (e.g., 50° C.) were used for drying thecoatings. The coating parameters, used for making the transparent filmof 8515, are as follows:

WEB/FILM: 12" wide, 0.1 mm thick Cronar® film.

VISCOSITY OF THE EMULSION: 700 cP.

COATING RODS: 20 mm diameter, #60 (60 cells/inch) helical gravure

COATING ROD SPEED: 36 rpm

COATING TECHNIQUE: Reverse roll gravure

WEB SPEED: 1.3 meter/minute

DRYING PATH: Total 24 feet, 7 feet before oven, 17 feet in oven.

DRYING TEMPERATURES: Three zones, (First: 40° C.; Second: 45° C., andThird: 50° C.).

THICKNESS OF PEl/BA/8515: 15 microns.

THICKNESS OF SUPERCOAT/GELATIN: 3 microns.

TRANSPARENCY: 70%

Example 23

Spatial Resolution: In order to determine spatial resolution of thefilm, a resolution target (USAF 1951 Target Neg., Product #70.6035, Madeby Rolyn Optics Company, Covina, Calif.) was used. A UV lamp (4 watttube lamp, Model UVG-11 of UVP Inc., San Gabriel, Calif.) covered with ametal foil having 3 mm hole was used to irradiate the film. The film ofExample 22 coated on one side was placed in contact with the resolutiontarget, the coating facing the target, and exposed to short wavelengthUV light from a distance of 20 cm for a few days. Though most of the UVlight was absorbed by the glass some light did penetrate through. Apattern of the target was obtained. All elements of Group 7 wereresolved which corresponds to more than at least 200 lines permillimeter. When the film was fixed by heating at 80° C., there was verylittle loss of resolution.

Example 24

Beam Imaging and Dose mapping: In order to determine the radiation dosemapping (beam data acquisition, e.g., across-beam-dose and depth-doseprofiles) large pieces (about 30×45 cm²) of pieces of film of Example 22were placed parallel and perpendicular to the beams of 10 MeV X-rayradiation, 18 and 12 MeV electrons and 15 MeV neutrons. The images ofthe beams were obtained. The penetration of electrons was the lowest.Neutrons and X-rays penetrated significantly deeper.

Example 25

Image of Body Phantoms: In order to demonstrate that the film can beused as a verification film, (1) a skull phantom was placed on the filmof Example 22 and irradiated with 200 rads of 20 MeV neutrons withoutusing any build-up device and (2) skull and palm phantoms were placedonto the films and irradiated with 200 rads of 10 MeV x-rays. In thecase of the X-ray irradiation, the film was loaded in a Kodak cassette.The image of the phantom was very weak in the case of neutrons mainlybecause of the lesser sensitivity of the film. However, a reasonablygood image was obtained with X-ray radiation. Some features of theanatomy were noticeable in the case of the skull phantom irradiated with10 MeV x-rays.

Example 26

Image of phantom with diagnostic X-ray: A hand phantom was placedadjacent to the film of Example 22 and irradiated with 200 rads of 100KVp x-rays. FIG. 5 shows a black and white photograph of the imageobtained on the film (the areas receiving higher dose, e.g., tissues,were red in color while those receiving lower dose, e.g., bones, werewhite to faint pink). The image of the phantom is very sharp. The filmused in this example had no convertor in the under coat, radiationsensitive coat or top coat for diagnostic X-ray exposure. Hence itrequired a much higher radiation dose for imaging. As shown in Examples28-31, the X-ray dose required to obtain the image can be reduced byabout a few orders of magnitude by using convertors in the undercoat,radiation sensitive coat and/or top coat. Selection of properconvertors, their concentrations and other experimental conditions canfurther reduce the dose required for imaging with diagnostic x-rays to afraction of a rad.

Example 27

G-VALUE OF 9010: About 4 grams of 9010, crystallized from isopropanol,was sealed separately in several black plastic bags and irradiated withdifferent dosages, 25-5,000 rads of 20 MeV neutrons, 12 MeV electronsand 10 MeV x-rays. The unreacted diacetylene in each sample wasextracted with isopropanol using a soxhlet extractor and the amount ofpolydiacetylene formed, and hence percent conversion to polymer, wasdetermined by weighing the extraction thimble before and afterextraction. X-ray radiation is the most effective in inducingpolymerization while neutrons are the least. The G-value, (number ofchemical events, in the present case number of monomer moleculespolymerized, per 100 eV of energy deposited), was determined using thefollowing equation: ##EQU2## Where, G.sub.(-m) is the G-value forpolymerization of the monomer, N is Avogadro number, C is fractionalpolymer conversion, M is molecular weight of monomer, and D is dose inrad.

The G value at zero radiation dose, G.sub.(-m,O), was determined byextrapolating plots of G-value versus radiation dose to zero dose. Thevalues are reported in Table 5.

Example 28

Effect of convertors in the radiation sensitive coat on theamplification of the image: To a 15 gram emulsion of PEl/BA/9010prepared according to the procedure similar to that described in Example21 were added 0.5 gram different inorganic compounds listed below. Themixtures were stirred to dissolve the salts. The emulsion-mixtures werethen coated onto Mylar® with a #30 wire wound rod. The coatings wereallowed to dry at room temperature and then irradiated with 254 nm UV,60 rads of 60 KVP x-rays, 100 rads of 10 MeV x-rays and 12 MeVelectrons. The optical density of the coatings were measured before andafter the irradiation. The results are summarized in the following Table9:

                  TABLE 9                                                         ______________________________________                                        Optical Density of Film containing different Convertors in the                Radiation Sensitive Coat.                                                     Optical Density                                                                      Radiation: None    X-ray  X-ray  Electrons                             Con-   Energy:            60 KVP 10 MEV 12 MeV                                vertor Dose (rads):       60     100    100                                   ______________________________________                                        None              0.05    0.14   0.08   0.08                                  Bal.sub.2         0.07    0.30   0.12   0.11                                  BaSO.sub.4        0.06    0.26   0.11   0.10                                  BaBr.sub.2        0.06    0.36   0.10   0.09                                  BaCl.sub.2        0.06    0.32   0.10   0.10                                  Pbl.sub.2         0.05    0.43   0.09   0.09                                  MgCl.sub.2        0.05    0.23   0.08   0.07                                  Kl                0.05    0.38   0.08   0.08                                  KBr               0.05    0.34   0.09   0.07                                  Nal               0.05    0.38   0.08   0.07                                  NaPO.sub.4        0.05    0.16   0.09   0.08                                  Snl.sub.4         0.05    0.33   0.08   0.07                                  H.sub.2 WO.sub.4  0.05    0.36   0.08   0.08                                  ZnO               0.10    0.36   0.19   0.19                                  ZnBr.sub.2        0.06    0.37   0.10   0.09                                  Znl               0.05    0.34   0.09   0.8                                   ZnSO.sub.4        0.05    0.25   0.08   0.08                                  CsBr              0.05    0.36   0.07   0.07                                  Csl               0.05    0.38   0.08   0.07                                  ______________________________________                                    

Example 29

Effect of metal convertors on the amplification of the image;polymer/metal complex added into the emulsion: To 10 gram of thePEl/BA/9010 emulsion prepared according to the procedure similar to thatdescribed in Example 21 were added 10 gram samples of different metalcomplexes of PEl listed below:

PEl/Metal complexes:

15% BaBr₂ in 30% PEl

10% Bal₂ in 30% PEl

5% CsBr in 7.5% PEl

4% Csl in 7.5% PEl

9% Pbl₂ in 10% PEl

26% Znl₂ in 30% PEl

2% ZnO in 30% PEl

25% ZnSO₄ in 20% PEl

The mixtures of emulsion-complex were mixed and then coated onto Mylar®with 1 #30 wire wound rod. The coatings were allowed to dry at roomtemperature and then separately irradiated with 254 nm UV, 60 rads of 60KVP x-rays, 100 rads of 10 MeV x-rays and 12 MeV electrons. The opticaldensity of the coatings were measured before and after the exposure. Theresults are summarized in the following Table 10:

                  TABLE 10                                                        ______________________________________                                        Optical Density of Film containing different Convertors in the                Radiation Sensitive Coat.                                                     Optical Density                                                                      Radiation: None    X-ray  X-ray  Electrons                             Con-   Energy:            60 KVP 10 MEV 12 MeV                                vertor Dose (rads):       60     100    100                                   ______________________________________                                        None              0.05    0.14   0.08   0.08                                  Bal.sub.2         0.14    0.58   0.18   0.18                                  BaBr.sub.2        0.04    0.21   0.05   0.06                                  Pbl.sub.2         0.03    0.30   0.06   0.06                                  ZnO               0.04    0.12   0.05   0.06                                  Znl               0.04    0.34   0.06   0.06                                  ZnSO.sub.4        0.03    0.19   0.06   0.05                                  CsBr              0.03    0.27   0.06   0.05                                  Csl               0.03    0.27   0.06   0.05                                  ______________________________________                                    

Example 30

Effect of convertor in the top coat: The single side coated 8515 film ofExample 22 was coated with a #30 wire wound rod using the followingsolutions:

15% BaBr₂ in 30% PEl

10% Bal₂ in 30% PEl

5% CsBr in 7.5% PEl

4% Csl in 7.5% PEl

9% Pbl₂ in 10% PEl

26% Znl₂ in 30% PEl

2% ZnO in 30% PEl

25% ZnSO₄ in 20% PEl

The coatings were dried at room temperature and were separatelyirradiated with 60 rads of 60 KVP x-rays, 100 rads of 10 MeV x-rays and100 rads of 12 MeV electrons, Optical density measurements were takenbefore and after the exposure. The results are summarized Table 11:

                  TABLE 11                                                        ______________________________________                                        Optical Density of Film containing different Convertors in the                Top Coat.                                                                     Optical Density                                                                      Radiation: None    X-ray  X-ray  Electrons                             Con-   Energy:            60 KVP 10 MEV 12 MeV                                vertor Dose (rads):       60     100    100                                   ______________________________________                                        None              0.04    0.13   0.08   0.08                                  PEI/BA            0.10    0.31   0.14   0.13                                  PEI/Bal.sub.2     0.09    0.45   0.12   0.10                                  PEI/BaBr.sub.2    0.09    0.29   0.11   0.10                                  PEI/CsBr          0.09    0.54   0.12   0.10                                  PEI/Csl           0.09    0.55   0.12   0.11                                  PEI/Pbl.sub.2     0.09    0.67   0.12   0.11                                  PEI/Znl.sub.2     0.09    0.55   0.13   0.11                                  PEI/ZnO           0.08    0.30   0.10   0.09                                  PEI/ZnSO.sub.4    0.09    0.44   0.13   0.12                                  ______________________________________                                    

Example 31

Effect of convertor in the undercoat coat: A polyester film was coatedwith the following complexes using a #30 wire wound rod:

10% Bal₂ in 30% PEl

9% Pbl₂ in 10% PEl

26% Znl₂ in 30% PEl

25% ZnSO₄ in 20% PEl

The coatings were dried in an oven at 60° C. for an hour. The films werethen coated with the emulsion described in Example 21 using a #30 wirewound rod. The pieces of the films were irradiated with 60 rads of 60KVP x-rays, 100 rads of 10 MeV x-rays, and 100 rads of 12 MeV electrons.Optical density measurements were taken before and after the exposure.The results are summarized below in Table 12:

                  TABLE 12                                                        ______________________________________                                        Optical Density of Film containing different Convertors in the                Under Coat.                                                                   Optical Density                                                                      Radiation: None    X-ray  X-ray  Electrons                             Con-   Energy:            60 KVP 10 MEV 12 MeV                                vertor Dose (rads):       60     100    100                                   ______________________________________                                        None              0.05    0.14   0.08   0.08                                  PEI/Bal.sub.2     0.09    0.42   0.11   0.10                                  PEI/Pbl.sub.2     0.07    0.61   0.11   0.11                                  PEI/ZnSO.sub.4    0.07    0.47   0.12   0.11                                  ______________________________________                                    

Example 32

Imaging with a UV laser: A piece of film of Example 22 was exposed to a256 nm Krypton fluoride laser. The beam had diameter of one micron.Parallel lines and different shapes were drawn with the laser. The linesand the shapes were clearly visible as dark red lines under amicroscope. The film was fixed by heating at 85° C. for 5 minutes. Theimages turned dark blue/black. The results show that the film can beused for writing information and printing images with a UV laser.

Example 33

Nondestructive testing of Industrial Parts: A piece of welded pipe wasplace on a piece of the film of Example 22. The assembly was irradiatedwith gamma rays from iridium for 20 minutes. A red image of the pipewith lighter image of the welding was obtained. Thus, welding seams andirregularities or flaws in the welds can be detected by the film of thisinvention.

Example 34

Inks, printing and color changes: Inks of 166 and TP41 were prepared byhomogenizing 6 ml of 50% solutions of the diacetylene inmethylethylketone in a commercially available raw ink (ink withoutpigment), Joncryl 142 (a water based ink of Johnson Wax, Racine, Wis.).The inks were milky white emulsions, Some papers were printed using thescreen printing technique by squeezing the inks of this Example and thatof Example 21, through a screen. Colorless/white images of the screenwere obtained. When exposed to 254 nm UV light, the images becamevisible in colors; 166 in red color and TP41 in blue color. When heatedwith a hot air blower, the red color of 166 changed to blue color andthe blue color of TP41 became red. Upon further heating to a highertemperature, the red color of TP41 became yellow and that of 166 becamered. When cooled to room temperature, TP41 turned red and 166 turnedblue. The images were irradiated again with the UV light. The TP41 imagebecame purple-blue while that of 166 did not develop any color. Upon thesecond heating, the TP41 image changed to red color at lower temperatureand yellow at a higher temperature. These types of inks can be used as"security inks" in printing, e.g., documents, to establish theirgenuineness and authenticity.

We claim:
 1. A self-developing film for developing an image fromexposure to X-ray, gamma ray, or electron, radiation comprising at leastone conjugated diacetylene, or cocrystallized mixture thereof, capableof undergoing a color change upon polymerization when contacted withultraviolet light, X-rays, alpha particles, or electrons, therebyforming an image; a binder; a convertor, wherein said convertor is amaterial which can emit lower energy radiation for polymerization ofsaid diacetylene after contact with X-radiation, gamma radiation orelectrons; wherein said image is capable of being fixed by heating saiddiacetylene at or above its melting point, or at the temperature atwhich the diacetylene undergoes a phase change to a radiation inactivephase, and wherein said film is transparent.
 2. The film of claim Ifurther comprising:(a) at least one layer containing said at least oneconjugated diacetylene, or cocrystallized mixture thereof, capable ofundergoing a color change upon polymerization induced by ultravioletlight, X-rays, alpha particles, or electrons, thereby forming a coloredimage; (b) at least one layer containing said binder and said convertorbeing in combination, being a complex or solid solution, wherein saidconvertor is a material capable of emitting ultraviolet light, lowenergy X-rays, alpha particles, or electrons upon contact with higherenergy X-ray, gamma ray, electron, radiation; (c) a substrate upon whichsaid layers (a) and (b) are deposited thereon, wherein layer (a) andlayer (b) are capable of being combined into one layer (ab), and saidcolored image is capable of being fixed by heating said diacetylene ator above its melting point, or at the temperature at which thediacetylene undergoes a phase change to a radiation inactive phase. 3.The film of claim 1 wherein said diacetylene is selected from the groupconsisting of: 2,4-hexadiyn-1,6-bis (n-hexylurethane);2,4-hexadiyn-1,6-bis (n-pentylurethane); 2,4-hexadiyn-1-mono(n-pentyl-urethane)-6-mono (n-hexylurethane); 2,4-hexadiyn-1-mono(n-hexyl-urethane)-6-mono (phenyl acetate); and co-crystallized mixturesthereof.
 4. The film of claim 3 wherein said diacetylene is aco-crystallized mixture of 2,4-hexadiyn-1,6-bis (n-hexylurethane) and2,4-hexadiyn-1-mono (n-pentyl-urethane)-6-mono (n-hexylurethane).
 5. Thefilm of claim 4 wherein said 2,4-hexadiyn-1,6-bis (n-hexylurethane) ispresent in the co-crystallized mixture in an amount of about 80 weightpercent or above.
 6. The film of claim 3 wherein said diacetylene turnsred upon irradiation.
 7. The film of claim 6 wherein said diacetyleneafter irradiation turns blue by heating at or above its melting point.8. The film of claim 1 wherein said convertor is selected from the groupconsisting of an element, alloy, salt, of mixture thereof of barium orlead.
 9. The film of claim 1 wherein the convertor is a metallic moietycovalently or ionically bonded to at least one of said diacetylenes. 10.The film of claim 1 wherein the convertor is a radio/electronluminescence or fluorescence phosphor which emits UV light, or lowerenergy X-ray or electrons when contacted with high energy X-rays, gammarays, or electrons.
 11. The film of claim I wherein the convertor is ametallic moiety intermixed with said binder in a complex or solidsolution combination.
 12. The film of claim I wherein said convertor isselected from salts, alloys, or mixtures of: Cr, Mn, Fe, Co, Ni, Zr, Ru,In, Sb, W, Bi, U, La, Cr, Zn, Mo, Ba, Pd, Ag, Cu, Pt, Pb, Au, Hg, Ti,Cd, K, Mg, Na, Sn, Cs, l; phosphors; fluorescent compounds; or cathodeluminescent compounds.
 13. The film of claim 9 wherein said convertor isselected from the group consisting of Bal₂, BaSO₄, BaBr₂, BaCl₂, Pbl₂,MgCl₂, Kl, KBr, Nal, Na₃ PO₄, Snl₄, H₂ WO₄, ZnO, ZnBr₂, Znl₂, ZnSO₄,CsBr, Csl, ZnS, ZnCl₂, Y₂ O₂ S, CaWO₃ and ZnSiO₄.
 14. The film of claim1 wherein said convertor emits a lower energy radiation of 4 e V orabove.
 15. The film of claim 1 wherein said convertor is selected fromlead iodide, barium iodide, or mixtures thereof.
 16. The film of claim 1wherein said binder is a water soluble or water-insoluble polymer. 17.The film of claim 9 wherein said binder is a water soluble binderselected from the group consisting of: polyacids, polyamines,polyethers, polyalcohols, polyamides, and gelatin.
 18. The film of claim17 wherein said binder is selected from the group consisting ofpolyacrylic acid, polyvinylalcohol, polyvinylpyridine,polyvinylpyrrolidone, polyethyleneimine, polyethyleneoxide,polyvinylether, and gelatin.
 19. The film of claim 18 wherein saidbinder is polyethyleneimine.
 20. The film of claim 1 wherein said binderforms a complex with said convertor.
 21. The film of claim 1 furthercomprising (c) an undercoat layer.
 22. The film of claim 1 wherein saiddiacetylene is a co-crystallized mixture of 2,4-hexadiyn-1,6-bis(n-hexylurethane) and 2,4-hexadiyn-1-mono (n-pentylurethane)-6-mono(n-hexylurethane)in an 85:15 weight ratio, respectively, said binder ispolyethyleneimine complexed with the convertors and barium iodide. 23.The film of claim 1 wherein said diacetylene is in radiation activeform.
 24. The film of claim 1 wherein said diacetylene is in a radiationinactive form but is capable of being converted to the radiation activeform prior to use.
 25. A film of claim 1 wherein said resulting imagecan be further amplified or darkened by contacting with a dye whichbonds with the polymerized diacetylene.
 26. A self-developing film fordeveloping an image from exposure to ultraviolet laser radiationcomprising at least one conjugated diacetylene, or cocrystallizedmixture thereof, capable of undergoing a color change uponpolymerization when contacted with ultraviolet laser radiation therebyforming an image, and a polyethyleneimine binder complex, forming atransparent film, wherein said image is capable of being fixed byheating said diacetylene at or above its melting point, or at thetemperature at which the diacetylene undergoes a phase change to aradiation inactive phase.